His argument was that because the top of Florida doesn’t protrude, Florida as a whole isn’t a peninsula. In hindsight, I think the word for what he’s describing is “island.”
He’s Chinese-Australian, so It’s not the people here in China he’s got a problem with, it’s white folk. He’s thinks that all white Americans have an inherent, genetic guilt about slavery (whether or not their ancestors had anything to do with it) and that all modern Germans must hate Jews because Hitler and the Nazis were a thing.
I don’t think there’s anything actionable, so I’m settling for avoiding / ignoring him.