Interesting thread.

As background to other readers, an "Incel" is a member of an online community of self-described "involuntary Celibates". What they hold in common is a rather poor track record with women. Also in common is their sense that this has nothing to do with their own doing or actions but that women themselves are banding together to prevent them from having relationships (sexual in particular). The 'dark web' is a great place to find groups of these Incels banding together. This grouping together only adds to their ruminations and beliefs women are intentionally denying them sex. In most cases, these men appear to be socially inadequate and extremely socially inept. There are stats out their suggesting a great many men with Aspergers and Autism fall prey and get roped into this growing community (note, I am not suggesting that all socially inadequate men choose to join such extremism).

They refuse to take personal responsibility for their failures. They blame women in general; that it is a feminist cause to deny their rights to sexual relationships. They exhibit at times a great deal of anger - so much so that some have taken their anger out violently against women

The OP has asked about personal responsibility of these men, specifically do they choose to act in such a way by free will or have they been instructed in how to proceed.

I believe a great many fall into the second category. They discover the community and find themselves drawn in. Perhaps originally hesitant I am sure they find themselves a haven where they are free to express their alarming sentiments.