There’s nothing discriminatory about it. The comment isn’t saying non-whites or non-US workers are dumb or untalented; it’s saying that most of the more talented ones have relocated (emigrated) already.
It's implicitly saying that anyone in a low cost of living area must be less talented, because if they were talented then they would have emigrated.
This makes as much sense as saying all the nice Americans are the ones who decided to leave the US. But somehow that would be outrageous.