I listened to a podcast with someone who left the white power scene, and did some research. What I found in several sources is that extremists leverage your pain points. Feeling lonely? Unseen? Or did you grow up in a broken home? You can use that anger and redirect it towards the out-group of choice.

The wish to fit in is an important part, but I think it's first and foremost seeking for community. And when you feel lonely and are in pain, you are very vulnerable to people recruiting you into a cult or extremist group.

It could happen to anyone, but I think emotional maturity and coping skills play a big part in being able to identify and resisting extreme ideologies.