I think nothing beat the fact Slytherin still exist after the founder basically came out as a racist and want racist rule to be enacted, and also only accept student that's either a racist or speak parseltongue, and also the student literally live in a dungeon that's dark and gloomy. You'd think after a few years Salazar left the other founders will take note and change the way the house pick their student and the living condition of the student quarters, but nope.
And you'd think this is a story about the danger of tolerating the intolerant, then the writer became the intolerant lol.
I'm pretty sure the reason they keep to themselves is that the last time magic was public knowledge they were killed en masse during medieval witch hunts, or something. Been a loooooong time since I read the books.
You would think so, but look at the US and some other countries with racists of different kinds wanting to “go back to the good ol’ days” or wanting to push the societal problems to muggles (or immigrants/POC in the case of the US).