Meanwhile they'll call other countries "ethnically homogenous" mostly because they don't know anything about any other countries or literally thousands of years of finding any reason to hate each other.

It's a lot easier to not hate someone who looks just like you, speaks like you, believes in the same things as you, etc etc. You can put a lot of names to subgroups, but most Europeans are white atheists/Christians. If Europe wasn't ethnically homogeneous they wouldn't go this batshit insane over Middle Eastern immigration. Because that's not the reaction of people who are used to ethnic diversity; that's the reaction of people whose first time seeing someone speaking a non-European language outside of TV.