Loool I joined an incel forum a while back because I honestly could not understand their train of thought and I wanted to understand it here's what I learned from my short time there (I was too disgusted to stay for too long seriously guy I almost lost my sanity)
From my research I found out a couple things. Vast majority of these guys are suicidal. They'd typically joke about how they wanted to "rope" (1ncel slang for suicide) but im sure there was some truth to their jokes. Another thing the majority of them agree on is that "Chad's" (the top 10% of men) typically get whatever they want whatever female they want and never have to work for anything. They believe that if you are not part of the top 10-15% of men then you're doomed to be an 1ncel.
Another thing is that the whole 1ncel thing is a grey area. You don't have to be involuntarily celibate to be an 1ncel if that makes any sense. Stuff like paying for sex, marrying a girl from a third world country, or smashing an ugly girl doesn't mean you can't qualify as an 1ncel to them.
Last thing I learned is that they truly believe that women hate them because they're ugly (most of the time they aren't THAT ugly) and not part of the top 10-15%. All of them will tell you stories about how when they approach women kindly the women will stare at them with disgust and be absolutely repulsed by them just looking at them. They think "because women hate me I'll hate them back"
All in all, they view women as lesser being only meant to be on this world to breed with, they're suicidal, and they think they should be entitled to any women they choose. They're problems can easily be fixed they should work on themselves if they feel insecure, they should lower their standards or find a hobby that'll make them happy. The vast majority of these guys are disgusting but some of them are just a product of the harsh environment they were raised in (women can be cruel sometimes)