It sounds like these incel guys hate women — maybe for good cause; I don’t know. But if they go into a new relationship there’s a good chance the woman will feel those vibes and not want to invest time and energy with this person.
Or, he could hide those feelings for a while, a relationship develops, and then become verbally abusive when he feels safe to be himself. She walks; he whines. It becomes her fault.
I had the impression these guys never even got the first date, but perhaps you’re right. Sounds like something a good therapist could help resolve.