If I was searching for comparisons, I would look at Stockholm and suburbs in 1990s compared with present. I am told there are now areas where those born in .se and the police just avoid due to take-over by gangs of (some) recent immigrants.

> Scandinavian countries examples of low ethnic diversity

That's no longer the case and hasn't really been for a decade or two at least. Especially in Sweden.

What’s the argument supposed to be? Homogeneity in service of peace?

I’d rather live in a diverse hellhole than some whitewashed “utopia”.