Because people are close-minded and can't believe that some people are born loving people of the same sex, just like themselves are born loving people of the opposite sex.  It is shown throughout the animal kingdom that homosexuality is not just a human thing, but something that many animals partake in.\nI don't see why it matters to so many people anyway.  I mean, why do they care if loving someone of the same sex makes someone else happy.  Worry about your own happiness.\nTo each his/her own.\n:)