Why jinx the celebration of their love by bringing in such a hatred for the event? I don't get it.
It’s because, having been so “oppressed” for so long, the ultimate defiance of that “oppression” (getting married, which conveys state recognition upon the union) can also be used to drive their “oppressors” from the public square.
To many homosexuals (as is true with mant other “oppressed” groups) simple conveyance of equal rights isn’t enough. Those who oppose such rights, regardless of reasoning, must be punished for doing so. Both as a matter of revenge and as a warning/example to others.