I met an incel once, on a blind date. He was attractive (on the surface at least) and was a self declared 'nice guy'. He was anything but nice (please don't judge me to harshly for not picking up on the red flags straight away, I was very young, stupid and had poor boundaries and no self esteem). He treated me appallingly. He was rude, insulting and talked over me. He thought I should be grateful that he asked me out (I had a very low paying job, I couldn't afford university like he could). Told me that i should lose weight if I wanted to be with him (I was a size 8 at the time). He was so utterly foul that even in my stupid, weak state I wanted nothing to do with him. He was outraged at the end of the evening when I refused to sleep with him and said I never wanted to go out again. The rage! I was genuinely frightened at the time.
These Incels attitude is the problem, not their attractiveness or bank balance. When I met my husband he had no job and no money but was polite, decent and respectful.
These Incels need a man to set the straight. They aren't going to listen to women so why anyone thinks women could sort it is beyond me.
Much like the issue of male violence against trans women/gay men/gender non conforming men. The kind of men who think nothing of hurting a trans woman or effeminate man are usually also the sort of men who attack/rape/disrespect women. They don't care what women have to say, they do care what other men have to say.
This is not a woman's or feminist problem to fix imo.