I've always been curious about something for as long as I've been doing this.
My friends and I have been in debates and arguments with racial realists on the internet. They try to justify their racism by claiming that their belief in a hierarchy of superiority has scientific backing. This is also known as "scientific racism".
Many of them make a comment that I find incredibly ironic: That philosophical arguments have no substance.
Yet, the foundation of their own arguments is in the reliance on philosophical unity.
Philosophical unity is a natural sense of connection a group of people feels when they are connected through their language, appearance, attitude, and aspirations. There are little barriers in western society between people who are native to that area, so it's easy for them to get along.
So to settle another argument, the fact that more diverse areas tend to have a lower amount of trust says nothing about diversity, but in the masses' general mistrust in others who aren't a part of their circle of philosophical unity.
Race (or ethnicity, but either way you're probably calling it the wrong thing) does not have any inherent importance. Neither does nationality, until you actively participate in it.