So, as someone very familiar with his writing, I think the article that did him in was out-of-character, and likely a result of his chemotherapy.
The meaning, and of course the reality, of race differences in IQ is as difficult to discuss as it important.
When you adjust for IQ, is prison population 'fairly' racially mixed? Do our schools do good job of educating when normed by IQ? Just typing these last two sentences is difficult in our PC age. There is no question, adjusting for sarcasm his final article crossed the line. Shame, he is a great man.