>variation between different regions is small, thus blurring the lines between populations. Furthermore, variation within a single region is large, and there is no uniform identity

I can't wrap my head around this statement in a way that makes any sense. I'm really trying to be a good boy here, but it just sounds like semantics rather than anything meaningful. I would appreciate it if anybody explain this so it doesn't sound like something to shut preventing discourse from drifting to racist territories.