I don't know how much influence does genetics have on student success. There can be plausible arguments that it's 50/50 nature/nurture, 20/80 or 80/20.

However, it definitely is bullshit to claim "It's the same argument that has been used in favor of organized eugenics, and, just to fulfill Godwin's Law, also used in favor of the holocaust." as any evidence whatsoever about what nature/nurture proportion is the true one.