My thoughts on incels: Reactive attachment disorder, although it may only apply to children, may explain quite a bit. Caused by trauma, symptoms include difficulty expressing positive emotions, unexplained fear or unhappiness, watching but not engaging, and not usually seeking comfort in times of distress.
Other anxieties that could cause social isolation may be found in books like Healing Developmental Trauma. The thread for that one is under the subforum 'The Work.'
It is probably about being low on the social ladder or having difficulties in social interaction. It's not as complicated as politics makes it seem.