Are r&b, funk, soul and jazz the least controversial music genres or is it me?

To expand on your comment that "a lot of people don't consider [smooth jazz] actual jazz," there's been a tremendous amount of disagreement within the jazz community on what exactly constitutes "good jazz" or "real jazz" over the past century; it's not just whether or not you like Kenny G. Though the general populace may not have much of an opinion on the genre, its internal turmoil arguably makes it the most controversial one out there.

It's been a while since I've gotten into the sociological component of the music, but jazz's roots as a form of self-expression for certain cultural groups (mostly Black and Creole communities) introduces an extremely complex integration of identity "realness" to what would otherwise be reproducible performances comparable to any other. Because improvisation is so important to jazz musicians, and because jazz has historically had a great deal of resonance within Black communities, a significant number of jazz artists and critics have reached the conclusion that to perform jazz as a White person is an inherently different (and generally worse) form of creative expression than to do so as a Black person. i.e. there is such a thing as "White jazz," and the way the jazz scene has evolved since the genre's inception has highlighted the elements associated with this style to the detriment of the genre's "true" roots as Black music. The famous critic Amiri Baraka in particular comes to mind as a proponent of this belief, though there are many others. Personally I am not a huge fan of the idea of "Black jazz" and "White jazz," because (as I will explain henceforth) the distinction was never really that clear to begin with, and because it also implicitly erases the contributions to the genre from people of other racial identities. Generally I prefer terms like "hot jazz" to describe the energy of the material. I do think that it's very important to recognize the sociological component of the music and all associated debates, though. I don't wish to disregard the historical fact that jazz was, until being surpassed by rock and roll, the absolute embodiment of evil to the White establishment. We can laugh at that today, because jazz is frequently (and ironically) associated with being "classy," but it was highly subversive for its time.

The precursors to the smooth jazz of the 1980s extend back to the 1920s and earlier, when White theater owners and big band conductors actively sought to change the way jazz existed as a musical form to better suit the tastes of White audiences. From a socio-artistic perspective, this was problematic because the style specifically arose from explicitly non-transferable elements of Black identity. Jazz from the late 19th century had very little European influence relative to later iterations because it was fundamentally not created by or for White people. The sociological component of Creole jazz is too complicated for me to summarize in full, particularly because the concept of Creole culture was so intensely divided between the "more White" and the "more Black," but suffice it to say that the perceived Whiteness of certain Creole musicians (by other Creole persons) could be but was not necessarily a matter of cultural destruction in and of itself (Creole identities, by definition, tend to have a heavier synthesis of European constructs than more general Black identities; but their manner of expression has emergent qualities that offer it distinctiveness from the European tradition). There has always been a lot of diversity in the genre, it's just that the nature of that diversity has changed dramatically over the years.

The real issue came with jazz's commercialization and the subsequent assumptions by audiences that it was fair game for White musicians. You might be surprised to learn that the "King of Jazz" of the 1920s was Paul Whiteman, who was decidedly not Black. I personally find this characterization appalling, if nothing else because I consider many of his contemporaries far more musically interesting; for many critics it was primarily the overwhelming Whiteness of his band and not the music "itself" (not that it can really be extricated), or a mix of those factors. The symphonic jazz of the 1920s was not really an academic endeavor to synthesize disparate genres to the benefit of each one ("for art!"), but to appropriate and distort Black cultural expression in a way that paid very little homage to its foundations. Certainly there were also Black musicians who contributed to orchestral jazz fusion, like Duke Ellington, who is very highly regarded, but that brings us back to the earlier question of what should be considered "real jazz." Pretty much by definition, music performed by a Black person is "Black expression," though many critics have still called Black musicians sellouts if they adopted styles popular with White audiences for the purposes of acquiring fame and wealth (rather than it being "for the culture"). It becomes very muddy very quickly. Miles Davis is probably the musician who comes most immediately to mind here for his adoption of cool jazz specifically in opposition to bebop, which I will describe later. And then you have performers like the incredibly talented Bix Beiderbecke, who was White and worked under Paul Whiteman but who as far as I recall was not criticized in quite the same way, probably on account of his skill; and the similarly excellent Benny Goodman, who was White but also Jewish, an identity for which he faced a great deal of stigmatization. I think it's hard to argue that the swing era in which Goodman resided didn't strive to meet at least some European tastes, but there was definitely a huge divide between "acceptable" swing and the really "hot" stuff (toward which I think he leaned much more closely), regardless of the racial identities of the performers.

The most striking instance of jazz's racial divide is the bebop era in the 1940s. At that time it was very common for musicians to have spontaneous and legendary jam sessions in the coolest clubs of the coolest neighborhoods, and many Black musicians felt a growing resentment toward White players who "played jazz" but lacked the energy, creativity, or raw talent to truly innovate by themselves without copying Black musicians. This was attributed to their differences in identity; i.e. the motivation or inspiration to produce the best jazz was a bit harder to come by for White people who did not face the sort of quotidian discrimination and systemic oppression as the Black community, and who subsequently held worldviews not aligned with what was "hip." The entire premise of bebop was to create a form of jazz so fast, so technical, so difficult, so unpredictable, and so powerful that it could not be copied; it had to "come from the soul"—or it simply could not be produced with a level of quality comparable to the good stuff. Remembering again the improvisational nature of jazz, musicians like Charlie Parker, Dizzy Gillespie, Bud Powell, and others were adamant that the form was the new thing precisely because it found a way to re-center Black avenues of self-expression in a genre that had largely become populated by White influences. Musicians would hop into late-night jam sessions and find themselves in a race to keep up; after a while, inferior players would realize in the middle of a set that they had been completely eclipsed, unable to play off the unbelievably fast and technically precise melodies and rhythms of their counterparts, and would embarrassedly walk off stage, to be replaced by someone with more virtuosic ability. Only the absolute best of the best could really "bop," and those musicians tended to be Black (there were certainly exceptions, like Buddy DeFranco, but the roster had a pretty clear divide). Because the form was (naturally) always evolving, this attitude was a way for musicians to signal their membership in the "in-group" of jazz.

I would argue that jazz maintained a significant presence in the popular consciousness even as performers like Thelonious Monk hinted at the avant-garde with their revolutionary dissonances and rhythmic aberrations. Rather, my personal impression is that the genre fell out of the mainstream as popular music and rock and roll became more culturally dominant. I don't think this was the fault of jazz itself, just that it struggled to compete with newer instruments and sounds that emerged alongside the counterculture of the 1960s (there were various attempts at fusion, but I don't think they were as popular as pure rock ever was). In my estimation, jazz began to lose some of its racial implications as it became even more personal than bop, because then it became less about collective cultural self-expression in the face of blatant discrimination and more about musical innovation for its own sake, often regardless of what the audience thinks. Some jazz groups actively insult or otherwise show disrespect to the audience for even the mildest of offenses (this is part of the draw). More generally, many classifications start to break down once you get to a certain theoretical level. This is perhaps no better exemplified than in the free jazz of Cecil Taylor and Ornette Coleman, which, if I'm going to be honest, requires a very particular mindset to genuinely appreciate. I can find myself entering that space sometimes, but it's not for everyone. Structurally, I would equate academic jazz from this point onward somewhat more closely with contemporary classical music than any sort of jazz that predates it, insofar as it is almost exclusively appreciated by a very particular audience. It doesn't surprise me that some musicians, such as Wynton Marsalis, are very critical of the avant-garde, calling it inaccessible. In most semi-recent discourse on jazz, I see less racial commentary and more "how can we make jazz hip again?" I'm admittedly a bit out of the loop with the very recent jazz scene; the last time I went to any sort of performance was perhaps in early 2020 and a concert at a larger venue in Philadelphia a year prior, and ongoing circumstances have made it challenging for me to get back into the "swing" of things (as it were). Perhaps this is a "hot" take (…as it were), but I would question whether jazz can ever really be at the progressive forefront of the musical scene again without more heavily reintegrating both implicit and explicit social (read: racial) commentary into its messages. It's not like jazz musicians have forgotten the genre's roots, but the onus of fighting (and being criticized by) the establishment seems to have shifted in large part from jazz to rap over the past few decades.

I can no longer cite specific passages from memory, but most of my knowledge here originates from the compendium Reading Jazz (ed. Robert Gottlieb, 1999), which is something like 1000 pages long and records perspectives of musicians and critics on jazz from the genre's very inception. I haven't read the whole thing, but I would recommend it to anyone looking to become a little more familiar with the history of jazz music.