They literally, as a grown person in the Year of Our Lord 2022, used the word 'fee-fees' in an aggressive and hateful way.
I dunno what else to say to you if you cannot take a joke seriously.
And yes, if your feelings/fee-fees can be hurt by what someone says about a subject you like on the internet, then you really should rethink whether engaging in dialogue with anyone online is for you. I should think it is not worth the blood pressure issues.
I have been called many terrible things on the internet for having an opinion, told to go to a very hot place and push certain sharp objects up my orifices, and received death threats from people who live on the other half of the planet yet think I will be sleeping with a gun under my pillow in fear of them.

I just shrug and go on with my life. You really should not put this much stock into what other people think and say.
I care more about what the creators of things I like say and do than what the fandom does, honestly. Because unlike the fans, that does directly impacts my enjoyment of the material I like.
No it's pretty obviously not his point. HIs point was that people in a fandom can and should still talk to each other respectfully despite having quasi-religious schisms. I think however your response illustrates his point perfectfully, because you immediately leaped to an ad hominem attack that took what he said in the worst possible light and even went so far as to twist it. He never defended any of those behaviors. The whole passive aggressive asking him that question is rude in the exact same what that "oh you say you are a fan? Prove it.".
He's clearly opposed to aggressive and hateful behavior. Why isn't your post treated as such?
Thanks dude. You are one of the few people who gets what I said.
We might like different parts of a franchise, but we can still talk about it and just accept each other's opinion as ... well, just that. Opinions.
Example, when I was on my university acceptance exam (back then we still had those) I met and befriended a fellow student and found out we had a lot of common interests in computer RPGs, fantasy novels and turn-based combat videogames, aside from biology that we both came there to study. But we had pretty large differences too - he loved death metal and was always wearing shirts with downright satanic symbols, I was a devout catholic. He supported the socialist party as he came from a proletariat background, I supported the conservatives because my parents came from backgrounds with higher education. But, we became best friends quickly and stayed in touch even after university, because our common interests overshadowed our rather large differences in worldview. We still discussed the things we disagreed about, occasionally, like when elections came around (and eventually he got disillusioned in the socialists and changed his political views 180) but overall we did not let these differences stand in our way when we talked about Planescape Torment or the latest RA. Salvatore Drizzt novel.