I'll just answer all of these questions.
It should be legal.
No it is not wrong.
Obviously it should be legalized. Marriage is nothing but a legally
binding contract between two people. It has nothing to do with the emotions that they experience or anything like that (though obviously there's room for the symbolism of two people connecting and 'taking the next step', or whatever you want to interpret). It's just a document that can be used for legal purposes. It has nothing to do with ethics or religion at its core, so it should stay far, far away from those things.
“Mutual caring relationships require kindness and patience, tolerance, optimism, joy in the other's achievements, confidence in oneself, and the ability to give without undue thought of gain.”