You can have pretty much this exact same argument on an international scale. (I think it was Steve Sailer who broke PISA tests down by demographics -- the results are about what you would expect). It's always funny to see shitlibs attacking the U.S. education system and ask them if they're controlling for demographics. Guaranteed "Wow Just Wow" responses -- but it really is the exact same logic as is used in the video. Is the U.S. education actually much worse than (insert random European country) or do we just have a shit ton more Hispanics and blacks?

Incidentally, this doesn't even require race realism in order to be a devastating rebuke of the post-1965 immigration system. Let's say for the sake of argument that IQ gaps are entirely environmental -- we have the choice of bringing in people who will more or less instantly assimilate or we can bring in people that require massive wealth transfers, systemic privileges (Affirmative Action, diversity initiatives, etc.) in order to reach our level. Why in the world would we ever opt for the latter? Let alone how in the real world, we have the latter policies implemented and they STILL aren't at our level.