Why is it legal for auto insurance companies to charge males more for auto insurance than females with the same driving record?

It's "discrimination" in the sense that the two genders are not being treated equally. However, a common misunderstanding is that all discrimination is barred--it's not; only that discrimination specifically prohibited by law is prevented, such as gender based discrimination in education, employment, and housing. However, no law prevents insurance companies from "discriminating" in a wide variety of ways: charging men more than women; charging younger people more than older; charging residents of certain urban areas more than people in nearby suburbs; etc. It's unfortunate and unfair, but legal and common. The bottom line: most "discrimination," in the sense of treating one group differently than another, is allowed, especially in an insurance context.