> Studies like this are hard, because they're usually labeled 'racist', or it turns into an ad hominem attack on the authors, or struck down in the media for singling out some minority group.

I think you’re confusing studies with conclusions. What you’re describing doesn’t happen but what is common are studies finding a correlation which leads to someone claiming causation and then complaining when they’re criticized.

As an example, in the US it’s uncontested that some populations have worse academic performance. That doesn’t get criticized seriously. What does get criticism is when a right-wing commenter tries to say that this must be because of genetic causes or the popular euphemism “culture” – and that criticism is well deserved since that ignores all of the other explanations and checks which actual science would require and goes straight to the same conclusion which avowed racists have been pushing for centuries.