What you point out isn't (even we accept its true as described, which I will disagree with in a minute) about people being proponents of tabula rasa: the problem they have is not with the idea that either X or IQ have strong genetic determinants, but with the conclusion that they are correlated.

And, actually, I would argue that in the real world, the correlation isn't even the thing that's problematic, its when the correlation is used as a basis for accepting discrimination on the basis of X. No one is upset about the widely known height/IQ correlation, but that's because no one is using it to justify discriminating based on height, because it is an easily-visible proxy for IQ.