Well, that was a different reference in GP's post. You can go read it. Heritability is definitely a thing, but far from the only thing and it isn't simple Mendelian inheritance - there are many components to intelligence that reflect differently in gene transfer and so while you can see a correlation in specific individuals and their immediate ancestors there are lots of exceptions and its probably a mirage - if seen at all - in any large demographic. See my other comment on the problems with eugenics in this thread.

Attacking IQ test is like vaccine denialism. People don’t like the fact that requiring individuals to cooperate can enhance health outcomes for the group as a whole. Similarly, people don’t like the idea that some individuals are just born smarter than other individuals.