Exit visas? Wow I never knew such a thing could exist. If you are a citizen of a country you should always be allowed to travel to that country unless you're arrested for committing a crime elsewhere.
It is a way to check you before you leave. Like a security guard checking your bag before you leave a store. Do you owe money, have legal trouble, etc. I am not saying it is right but that is how it is viewed.
Philippines has one. They treat you like criminal when you try to leave.