Culture is an expression of genetics.

Genetics is the sole factor, but it's not the only factor, and it may not even be the most influential factor. If that were the case, then we would not have seen Black culture deteriorate so much in the last 50 years. Take crime rate for example. That's the biggest thing most people have with Blacks and is fairly quantifiable. If you look at facts, you'll see that high Black crime rates cannot be primarily the result of bad genes. I justified this in a previous thread earlier. I'll just copy and paste it here:

The average imprisonment rate today is 0.47%, with Whites around 0.26%. The average imprisonment rate for Blacks in 1960 was 0.44%. And that was with blatant racism, so that figure may over-estimate Black criminality back then. Since Blacks genes have not changed much since 1960, then that indicates that the Black population is not genetically incapable of living at least as peacefully as they did in 1960. If the Black genes caused the Black imprisonment rate to be 0.44% in the 1960s, then I see no reason why the imprisonment rate can't be reduced 0.2-.3% (the White range) with less poverty, less systematic racism, and "better genes" (since European ancestry for Blacks has increased since 1960).

For reference, the current Black imprisonment rate is 1.46%. What caused the increase from 1960? That's an entirely different argument. However, we do know that the cause of the increase in crime was not a change in genes. Therefore, we can theoretically get Black crime back to those lower levels, at least. In fact, that's what appears to be happening now; in the past 13 years, the Black imprisonment rate has been dropping rapidly (from 1.8% to 1.46%). Also, the total number of violent Black criminals today is half of the total number of violent Black criminals 20 years ago. And that's the total number of violent Black criminals. Since the Black population has increased since then, the violent crime rate for Blacks has decreased dramatically; it's probably about 35-45% of the violent crime rate for Blacks 20 years ago (based on a rough estimation). So it is definitely getting better.

Unless they're intelligent, which only about 10% of blacks would be considered above average (50th percentile in IQ scores) if judged in comparison to white people.

Actually, that figure is close to 16%. And if you assume that at least ~30% of the Black White IQ gap is environmental (which is a fairly low estimate), then the Black IQ would be about 5 points higher, meaning ~20-30% of them would be above average. Prevent the least intelligent Blacks from reproducing and that number is even higher.