Well I would hope the US government would not perform genocide.
The earliest known inhabitants of Kosovo were called Illyrians by both Greeks and Romans. Albanians today claim to be direct descendants of the Illyrians. This is all before the 19th century. Ofcourse
the Serbs dont agree with this.
I think trying to solve the problem is beyond my talent/depth, but my answer to your statement/question still remains the same, that NATO took action to probally avoid another world catastrophe of the slaughter of thousands of people.