I am not a moderator, nor was I around when you were in the room, but maybe let's start with the very first thing you said when you entered the room:
@DylanWilson "Like seriously, some people were putting forth arguments for a biological basis for racism and sexism. What the actual f-?"
There is a biological basis for racism and sexism.
(Just to be clear, before the line break, we have user "Patriot" quoting Dylan Wilson earlier in the chat, and after the line break, we have user "Patriot" responding to Dylan Wilson.)
When Dylan made his comment, he was observing that even earlier in the chat people were trying to justify racism and sexism biologically (yes, you heard that right. That's been the state of discussion in the chatroom). So user "Patriot"'s response appeared to be claiming that racism and sexism were indeed biologically justified. Judging by the ensuing conversation, most people in the room were accordingly horrified, especially given
user "Patriot"'s past use of hate symbols,
previous comments, and
provocative username.
User "Patriot"'s comments after that appear to clarify that they were arguing, not that racism and sexism were biologically justified but that there are biological explanations for the existence of racism and sexism, which is not so horrifying. Notably absent from user "Patriot"'s comments was any acknowledgement that racism and sexism are not justified.
I think at this point the damage was done. I think the moral of the story is: if you act like a racist / troll (see bullet points above), people are going to interpret your further words and actions as those of a racist / troll. And I think that's your problem, not anybody else's problem.
EDIT:
User "Patriot" comments below that they think they were "too cautious" in not attempting to justify racism or sexism. So it seems I was too generous above, and I for one am through with sharing a forum with user "Patriot".