I think that's an area where the average person in the U.S. struggles. For all our issues with race, we are generally fairly integrated, so the thought that national borders need to very closely reflect ethnicities isn't top of mind.
Serbia proper has not seen much war other than the NATO bombing, and if you look at population statistics from 1991 and 2001 census in Balkan countries, you'll notice that it was mostly Serbian population that ended up displaced: instead of looking at the news narratives, we've got an opportunity to look at outcomes this far removed from the events.
USA has systemic, widespread racism, which is harder to get a concentrated effort against since the 0.1% minority inflicting harm with it are spread around a huge area and 300M+ people.
In tiny countries like Serbia (7M), Croatia (4M), Bosnia (3M), Kosovo (1.5-2M), an unscrupolous populist like Vučić or Kurti can easily get the entire minority acting together, and 0.1% ready to do damage can do a lot of damage against the other peaceful 99.9% who are slow to react.
And once shit hits the fan, it's "us" vs "them", so hard for voice of reason to prevail on either side.