There are no downvotes (which is a very good idea) and we are sorting by activity anyway. So what if we took the next logical step and got rid of the entire voting system? Please hear me out! :)
(1) Up-voting does not encourage quality postings (see, for instance, https://medium.com/the-physics-arxiv-blog/data-mining-reveals-how-the-down-vote-leads-to-a-vicious-circle-of-negative-feedback-aad9d49da238 ; yes the article also covers the up-vote).
(2) Anecdotally, up-voting discourages quality postings. I have often been frustrated because well-thought-out comments (by me or by others) got one hundredth of the up-votes of a strategically placed "lol" or something similarly trivial. People upvote things that evoke an emotional response, not things that make them think. (Source lost, unfortunately.)
(3) Up-votes are time-critial. Being the first one to comment often assures getting the most up-votes, which can lead to (2), to "first" posts, and to quick posts instead of well though-out comments.
(4) (Edit!) Up-voting can create an echo-chamber, because quality if measured by popularity.
All in all, voting is just a social media habit without any benefit and with the possibility of a large detrimental effect on posting quality. Old-school Web fora and Usenet worked fine without it and quality was (arguably) superior.
Would you really miss the option to vote? Is it worth the detrimental effects?
Edit: fixed the link to the article. Thanks!