I don’t care if they’re being genuine or not and don’t feel a need to prove it one way or the other. I will treat anyone who is defending Nazis as if they are genuinely Nazis themselves because at the end of the day, that’s what they’re pushing for, intentionally or not.
The damage this can cause does not change if it was intentional or not, so our reaction to it should not change either.
Their initial comment was complete nonsense, and sarcastic derision is one of the few things that actually upsets people like that who ignore the content of the conversation while also pretending to have the moral high ground. Their point is often to get people arguing amongst themselves instead of realizing they just shifted the conversation from “Here is a Nazi in Indiana” to “You can’t prove that Chinese speakers aren’t Nazis.” (Like we’re doing now.)
What would you have called them out for that fits better than moving goalposts or a strawman argument?