All sexes are protected classes. All races are protected classes. All national origins are protected classes. etc.

Except when you're in the majority, being white and male and a US citizen (in the US) isn't something you ever get discriminated against for. So this "protection" you talk about is pretty useless; if someone wants to discriminate against someone like me, they find some other convenient factor that isn't protected.

They're also likely to do that if you're in the minority.

The problem is the effectiveness of the rules, not that they don't cover everyone.