Earlier quoted context omitted.
The unstated argument to all the homogeneity arguments I've come across (intended or not) is: "We are too bigoted for that to work here, we'd never allow the $OUTGROUP to have it that good", with a side-dish of "they'd be bigoted too, if they weren't homogeneous". When laid bare, it's an appeal to ignorance.
I can't speak for all those who've made homogeneity arguments, but I've made them before in the context of Norway and will say this: Often, you'll hear people say something like, "Norway did X and it works, so we should do X in the U.S." These are typically fairly naive claims. Regardless of the normative dimension of the claim (whether X is worth doing in the U.S. in the first place), there is a non-trivial amount o…
We also have a much more diverse population than Norway, so if anything, US should be looking towards us for inspiration.