I disagree. Say that many members of the royal family have hemophilia. Is this due to genes, or environment? If it is genes, you can try to track down who has the gene, and not marry any of those people to your current monarch. If it is something in the royal water supply, you can track that down. If you say "It's both!", you are unlikely to solve the problem.
This applies to pretty much every case where people argue whether something is genes or environment. The claim that you can't call some things mainly genetic and some things mainly environmental is, we know with a very high degree of certainty, false. In most cases, the motivation for this claim is, I think, to avoid the unpleasant possibility that the answer is "genetic".
I never actually considered this viewpoint. But you know, the Tooby and Cosmides quote attacks the false dichotomy of "Everything is genetics! It's all programmed from before you're born!" and "Blank slate! Absolutely nothing is determined by anything other than experience!" both of which are nonsense.
But it also doesn't support the false third option, "You found a genetic basis for autism? Racist!"
Here's the new thread for posting quotes, with the usual rules: