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](https://chat.stackexchange.com/transcript/message/55299517#55299517) 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. 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](https://meta.mathoverflow.net/questions/3981/why-was-there-pushback-on-a-users-profile-image?noredirect=1&lq=1),

 - [previous comments](https://meta.mathoverflow.net/questions/4671/why-was-my-dissenting-viewpoint-in-a-post-about-diversity-censored), 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.