It's not diversity that is the problem. It's sub-saharan Africans and MENA muslims, there I said it. Their criminality, especially Africans and their diaspora, is scary. There are very few places in the west that are majority African/diaspora that are safe.
A place where there are many different european and east asian nationalities isn't scary.
Diversity is usually an euphemism for violent groups.
For example, Detroit is actually one of the most homogeneous cities in the USA, but it's "diverse".
You don't see many people complaining about diversity because of the chinese or vietnamese(hmong excluded).