Most incels, anecdotally, are either raised by single mothers or closer to their mothers/the feminine influences in their lives rather than the masculine. They either picked up or were raised with the belief that identifying closely to the feminine (being nice, submissive, polite, and passive in sex) will lead to dates with women. And not only that, along the way they internalized the idea that women are essentially better and purer than men. If you want any proof, look at the preferred art form of the incel – anime. Not anime in the literal definition, an artistic form of animation found in Japan including high quality works such as Akira, Lain, etc. but anime in the more colloquial sense – a form of animation which panders to a male demographic and which mainly acts to deliver “waifu” characters who can be sold and merchandised to otaku as a solution to their romantic woes. Both otaku and the incel, with their inbuilt idealization of the feminine (and subconscious fear/loathing of the masculine – see the stark lack of masculine male characters in the “anime” I have been describing), tend to consume plenty of the many works which cater to them.
Hence, I would argue that most of the incels – posting here or on cuckchan – started out as feminists. Perhaps lukewarm, but feminists nonetheless. Their progression from feminist to anti-feminist came as the feminists (and women) broke from the ideal they held in their hearts. That women would choose a man for intelligence or kindness, non-masculine traits. So they fashioned a sort of ideal form of themselves in their mind. Call it the gentleman, the fedora, the white knight, or the nerd – they abandoned their traditional gender role and then condemned society for abandoning them. Most incels have this ideal form within their mind, a sort of fortress or sanctuary which permits them distance from the world. For this reason they are almost impervious to the red pill, because while they can internalize that women despise them, they can always retreat to the safety of their sanctuary – their idealized self image – and condemn women instead, for not appreciating them.
Hence when the world/society increasingly attacks and mocks them – mocks that image of the perfect man that they and others implanted in them. They are still stubbornly loyal to that feminist picture of the “good man”, completely unaware that that good man never existed. That they misinterpreted what the feminists were describing.