Scientific-infused racism is still racism. Racism is the concept that racial differences infer superior or inferior ability. I think calling this a racist matter is pretty much in line with the dictionary.
Dr. Watson is, generally, saying that 'there's no reason to think that during the period our populations were "separated" that one population did not inherit more genetic markers significant to intelligence over another."
To me, while he has a point, it also sounds rather meh... in regards to evolutionary time, the current models suggest that our populations weren't apart all that long.... and since then, racial populations have intermingled enough that whose to say what genetic ancestry who has.... it's all a crap shoot. Our populations, especially in the West, don't really hold any racial identity... nor have they in at least the last couple thousand years... so any discernibly superior genetic material is probably all over the place by now... throughout people of all races in our population.
It takes a _lot_ less time to disperse genetic material than it does to build up a unique genetic profile in any population.
And, that said, basing someone's intelligence on the color of their skin is still a profoundly stupid direction to head, imho.