Ask HN: Why are technical interviews legal while IQ tests are not in the US?

Technical interviews often ask you to solve a problem on the spot quickly while someone is watching you.

Doing well on this activity is probably highly correlated with having a high IQ.

However, this is not how people work in practice and so the work may not need such a high IQ.

So why are such technical interviews legal in the US if IQ tests are not?