Even if made illegal, how does enforcement occur? The United States, at least, is notorious for HR being extremely opaque regarding hiring decisions.

Then there's cases like Japan, where not only companies, but also landlords, will make people answer a question like: "have you ever been part of an anti-social organization or committed a crime?" If you don't answer truthfully, that is a legal reason to reject you. If you answer truthfully, then you will never get a job (or housing) again.

Of course, there is a whole world outside of the United States and Japan. But these are the two countries I have experience dealing with.