I watched a couple of interesting documentaries on Netflix by filmmaker Deeyah Khan. In both, she sits down with people who have participated in violent ideological groups: Muslim jihadists and white nationalists. There are similarities between people who are attracted to both groups: young males with feelings of alienation and a desire for identity, belonging and power. Each documentary is less than an hour long and worth watching if you have Netflix or another way to stream them.
https://youtu.be/9HKgowHRZ1c
https://youtu.be/_vZOHaj7l78