Just to help you decode the lifetime of these interactions that awaits you.
Sadly, ad hominem attacks to reinforce group identity have become common across ideological groups.
The core contention is that he's a virginal loser with no friends. Men have insinuated this about each other, independently of political division, across the ages.
I do think it's helpful to understand when interactions are really just boiling down to this. Helps with the angst.
From the original claim of, "Nobody really thinks men are the cause of most of societies problems."
My response was, "While growing up I was taught and interacted with people who definitely thought men were the cause of most of societies problems."
The counter was, "You must be a terminally online virgin with no friends then."
From my perspective I have a rich social life that includes both genders and would consider myself a feminist. But it really is radicalizing that even mentioning experiences of casual misandry is met with accusations of social ineptitude
But, anyway, it's a confused conversation. It's helpful to zoom out a bit. The top-level comment is (partially) blaming feminist discourse for a social ill (increasing gambling addiction among young men). While politely stated, the claim is pretty inflammatory.
So part of what's going on here is that people are reacting to what they perceive as you defending that initial claim (which, again, is pretty inflammatory IMO) instead of just denouncing a bunch of people as incels and moving on.
Anyway, I will validate you. You are not taking crazy pills. You're just ... saying some things that are taboo to say. I would, uh, avoid ever using the word "misandry" in a setting where it can be associated with your real name.
That is simply so far out of the realm of believability. It is no different than if you said people started conversations with you by levitating and turning into flocks of bats.
But he said that this was common.