And what he said did fit with the definition in the lead of the English Wikipedia article on radical feminism.

To emphasize, since I personally had several discussions with that user: What he said did fit, only fit, and exclusively fit the wikipedia article on radical feminism. Other lines of thought seemed to not even parse - like comments in a block of code. The specific worldview and paradigm typical to radical feminism were all that could possibly exist and be real in the world, and nothing else seemed to even remotely make sense to that user, based on my extrapolation of their responses to various questions, comments, critiques and arguments.

I had productive discussions where I learned quite a bit, but that is definitely not the sort of behavior we want on LW by any stretch. AFAIK, that user learned exactly nothing useful from all those discussions, except perhaps on opinions among LW users.