One of my favorite subreddits to gawk at is Forever Alone (
https://www.reddit.com/r/ForeverAlone), which I'm sure has quite a lot of overlap with r/incels. The Forever Alone crowd primarily complains about romantic and sexual rejection, but there are also FAs whose interpersonal incompetence runs so deep they have no friends at all, and/or who are estranged from/rejected by their families.
And, occasionally, women who are Forever Alone post there--only to get told they can't possibly be FA because they have female privilege that allows them to get dick on demand (which is why there's a ForeverAloneWomen sub that went invite-only due to the never-ending parade of clueless mansplainers).
A small number of the FAs have mental illnesses, disabilities, or physical deformities that make finding a willing partner (or just dealing with day-to-day social situations) extraordinarily difficult. Their posts can be pretty fucking heartbreaking. But the great majority of posters are socially stunted dudes in their late teens and 20s who go on about "feeemales" as if they're not even part of the human species, rail against Chads, and spout bad evo-psych (so they're related to Redpillers in their woman-hate).
Lack of empathy, and the total inability to comprehend viewpoints and experiences beyond their own painfully narrow self-absorption, are pretty much hallmarks of FAs, as is weapons-grade self-pity. As a woman, I read a lot of posts and comments and think, "Of course you repel women--your personality is like an open sewer, and there's no hiding the stench." But just try telling any of them that--nope, it's always the feeeemales who are to blame, and "normies" offering advice are largely unwelcome.