"Contrary to what one might expect, for all of these personality effects the sex differences tend to be larger-- not smaller-- in more individualistic, gender-egalitarian countries. "
This finding, which apparently surprised and puzzled everyone, is very difficult to square with the idea that it is the societies/cultures that are creating these effects, because then you would expect the correlation to be the other way around. So not a magnitude difference, but a sign difference. Again, that observation, which has been replicated repeatedly with ever larger sample sizes and larger effect sizes, just isn't compatible with a cultural source.