Please stop being so condescending.

As in, deeply offensive to some people.

Heightened social trust in people of one's own ethnicity isn't a fact of life, it's just racism. It's what causes PoC to be profiled by law enforcement, on average have worse outcomes for the same crimes in the justice system, etc.

I know that this isn't just the way humans are wired. I met so many people (including police) in my life that I would consider truly "colorblind" and treat everyone with respect, regardless of their ethnicity.

Different shared cultural values (as opposed to just differing race) is also not as much of a problem as some make it out to be. First, most cultures of people that are immigrating to the US (I can't speak for Europe, I'm not very in the loop) have values largely compatible with Western ones. Second, most immigrants will at least somewhat assimilate into the culture of their host country, especially after a generation or two. Note, this doesn't mean throwing away their native culture.

I'd also like to point out that Woz's America was definitely NOT homogenous.

Frankly that's arrogant and narrow-minded view; homogenous culture might cause less conflicts and problems when the culture itself is one promoting that in the first place

This needs a citation. It's the sort of "common sense" all too often advanced by people with - frankly - racist or ethnonational agendas.

Are there any quantitative studies on this topic? It would be a stronger argument if a clear trend was observable over many countries.