I think the answer to this is pretty complicated.

They're all, across the board, emotionally ignorant. Either they were raised to stifle their emotions, or they learned to do it later in their adult lives as a defense mechanism, but things like empathy and vulnerability are disgusting to them. Other people are a means to an end. They literally fantasize about being sociopaths and think that emulating sociopaths makes them stronger people.

Second, their concept of self-worth revolves around acquiring sex and emulating a mythological ideal of masculinity. The highest possible attainment in their little cult is that of the "Alpha," and what do Alphas do? Get laid. The weak link in this chain of thought is the "Chad," almost always talked about as an enemy and an object of scorn. The only difference between a Chad and a Terper is that the Terper thinks he's smarter than the Chad and deserves sex more.

Which leads me to the fact that most of them are crushingly average but convinced that they're special. They're smarter, more logical, more masculine, more in tune with reality than everyone else. That desperate need to be special comes along with a certain entitlement, i.e. "I'm special, therefore I should be drowning in pussy, because that's the marker of a successful man to me."

Combine that entitlement and ego with a tendency to view other people (i.e. women) as tools, and you get a redpiller.