"Where were you radicalized?"

In all the discussions about whether "alt-right" should be tolerated, I tripped over the curiosity rock about what causes people to form or change political beliefs, what constitutes extremism, whether or not people come to realize they hold an extreme position, and how we can restore balance.

I got caught having a bad knee-jerk reaction here, and while I don't think my conclusion was wrong, it's taking a bit of work to unpack all of the knowledge, experience, and ideological biases that underlie it.

So, Tilders, was there a formative moment in your life (or close family/friend's experience) that set you on a course to uphold and defend a particular ideology, or did your position evolve over time?
Do you feel your adherence is "radical" or "extreme", and/or have others told you that you're an extremist/radical/ideologue?
What (or who) does your position make you unable to tolerate, if anything (or kind of person)?
Has your belief changed over time, or what do you think would change it?