I can't really see why so many people are against it.
Let's try to sum this up:
PROS: People loving each other can show their love for each other.
CONS: "It's unnatural"
Bullstuff. Homoloveuality is not unnatural. Dolphins, primates, penguins and 1500 more species have been reported to show homoloveual behavior.
What you call "unnatural" should be rephrased to "untraditional". Just because people used to believe homoloveuality was wrong, doesn't actually mean that it is wrong. By that logic, women and black people would still have no rights, we would still walk around naked (clothes, ewww) and we would have no language...