the causes of violent crime are biological in nature and then suggest biological interventions

For a moment there, I feared you'd speak of genetics and eugenics, but then

(someone on LessWrong recently suggested fish pill oils to correct for micronutrient deficiencies)

if you mean something as prosai as dietetics, I can totally get behind that; I find it easy to believe that crappy food induces cranky mood (and that, in the US, crappy cheap food is remarkably deleterious).

If you could acknowledge that culture problems and social multipliers have huge effects on adult criminality and success, and make policy decisions based on that (although this problem is very difficult) how many more lives could be saved?

Is this not acknowledged? Nay, is this not common knowledge?

If the political climate only allows you to say that different outcomes are the result of the discriminatory schooling system, those nasty racists and the prejudiced authorities

Putting the full blame on them is as absurd as fully absolving them. What insane political climate do you live in, that you'd have to settle for either fallacy?

if it describes the way the world is then its just science

I remain unconvinced that this is exactly the case, and, even though I can accept its provisional validity, with many caveats and reservations, I'm pretty sure the actual reality is more interesting than "blacks and latinos are born dumber, White-Jews and White-Asian nerds are born smarter, and White-Christians are born a little bit smarter than average".

Assuming this particular piece of knowledge matters, what are we supposed to do about it? Be more forgiving of teachers' inability to enable black students to reach some average standard? Allocate Jewish and Asian kids less resources and demand that they meet higher standards? Should we treat kids differently, segregating them by race or by IQ? What practical use do we even have for scientific racism?