I agree with a lot of this, and the framing is new to me and I really appreciate it. I especially appreciate the acknowledgement that there isn't necessarily anything wrong with having extreme beliefs; "extreme" is a label most often applied by antagonists of such beliefs. But I definitely feel like there can be a pipeline where one extreme belief may lead to others simply because they are also labelled extreme and n…
I've unfortunately lost a few friends to this process (why I felt compelled to comment). There's definitely a "rabbit hole" effect where there's a chain of beliefs that lead you further into extremism. A, B, and C may be "extreme" but benign, and then at some juncture, D comes along and that's the 'thing' that confirms their extremism is a correct response to the world.
I had this happen with an online friend who forgot he was talking to a mixed-race black man and started sending me what was effectively racist content (under religious pretenses), completely doe-eyed, almost leaning in as to see whether I was just as excited to "get on board" (I wasn't). That shift happened rather quickly and I later stitched together how he'd gotten there in his head (in effect online religious content on YT/Twitter).
That's the danger with entertaining extremism: one day, they won't be "just talking about stuff," they'll be strapping up the proverbial vest and you'll be thinking "but we just had a normal conversation..."