What if medieval times more often than not were full of racists, irrational crazy beliefs, brutality, killing, hate, all kinds of xenophobia, sexism, and other stuff we find despicable today. Trying to paint that time as a happy period, where everyone was integrated, and they lived together peacefully will backfire unless there is solid evidence to prove it.

> Then it matters that we get this right. Media can report on diversity of Global Middle Ages w/out trumped-up scholarship.

Exactly. I think there were areas at the intersection of trade routes where cities had multiple nationalities and faiths living together. One distinct feature was that it was tied to economic prosperity. As long as everyone was not starving and had a place to live, and trade was flourishing, living together worked well. I think picking one of those example might have worked better in this context. But in general if the audience was white supremacists, it's better to just ignore them and not engage, it's waste of time debating with crazy people.