I can't help but think that a lot of resentment from guys who aren't getting laid comes from society's notion that if you can't or don't get sex, it means you're a lesser human being and that makes it okay for others to hurt you. In that position, I could easily see a man resenting women as the gatekeepers of his full humanity, and that by not having sex with him, they're depriving him of it. It's very similar to some angry thoughts I had when I was younger, and in a worse timeline it's entirely possible I could've fully plunged into that same cesspit.
That isn't to justify any of the awful shit that incels say and do, of course - many reactionaries lay blame in the wrong place for very real problems they face - but I feel there has to be a connection there.
From what I've seen, right-wing "MRAs" don't want the material conditions of men to get better; they want the material conditions of women to get worse.
Much like reactionaries experience the same material conditions as us and go "must be the minorities fault"
Nothing scares a reactionary more than the "lessers" getting the same treatment that they do, or the possibility of being treated the way they already treat "lessers."