The law is you can't descriminate against a protected class. Lots of things are protected classes, like race and religion. Old age is, but young age isn't. Clothing choices in general aren't, but if it's a religous choice, it likely is protected.
Etc.
It's kind of weird that you can fire young people because they're young, but not old people because they're old. But it's not a paradox, it's just how the system is codified.
The law is you can't descriminate against a protected class. Lots of things are protected classes, like race and religion. Old age is, but young age isn't. Clothing choices in general aren't, but if it's a religous choice, it likely is protected.
Etc.
It's kind of weird that you can fire young people because they're young, but not old people because they're old. But it's not a paradox, it's just how the system is codified.