Is it normal for prostitution to be illegal?

That has always been so weird to me. It doesn't seem like something that should be the laws concern. Plus, I think it'd be a lot safer for the women/men doing this if it were legal. That way it could be an actual business, and they could get off the streets maybe.

Also like, you can legally have sex with anyone you want (if it's a consensual adult obviously), but it's suddenly illegal if you're paying them for it? Makes no sense to me.