I could never be an incel, but I definitely understand how you could get that way; most of what most men — especially average men — experience from women is coldness and casual cruelty.
I know the “reasons” women have for being this way, of course. But it doesn’t make it less psychologically damaging to experience.
With the decline of third spaces where women and men could hang out with no expectations and pressure, this was nearly destined to occur.