Let's say for the sake of argument that people with high IQ are more likely to have white-collar jobs which rely on intellectual ability, and people with low IQ are more likely to have jobs consisting mostly of manual labor. I would expect jobs to be distributed this way even in a theoretical society where IQ was a perfect measure of true intelligence, and where manual labor was respected and not necessarily lower-paid.

It stands to reason that the white-collar, high IQ voters would be less concerned with policies which affect manual laborers. These could include workplace safety protections, certification requirements, etc.

Smart people are equally greedy and corruptable.