Nobody has said it yet, so I will:

There is a homophobic cycle which is intrinsically evil, and the whole
opposition to same-sex unions is an inherent part of that cycle. Even
those who don't admit it.

It goes something like this:

1) Child learns in schoolyard that anyone who is 'different' is the
   subject of ridicule.
2) Child learns about homosexuals, and the terms 'queer' and 'fag'
   enter his vocabulary of derisive terms. (I personally remember
   being habitually called 'faaaaag' by a socially prominent girl
   in my 6th-grade class who took a dislike to me. I think it was
   right then that I became a (heterosexual) gay-rights activist.)
3) Child eventually (perhaps) has the moral formation to get rid
   of many of their prejudices. However, many of those same religious
   institutions which abhor racism, prejudice against those with
   disabilities, and even some measure of gender equality still
   teach that homosexuals are morally defective. Having fewer
   choices now of 'different' people to vent their hostility,
   child becomes even more hostile towards homosexuals. Expressions
   like "that's so gay" come out of the mouths of young people who
   would never think of using the n-word.
4) Hostility breeds contempt, contempt breeds ignorance, and ignorance
   breeds all sorts of myths about homosexuality and homosexuals.
   That they're apt to be child molesters. That they recruit. That
   somehow their lifestyles diminish or threaten those of
   heterosexuals.
5) Myths get turned into rationalizations for why homosexuality IS
   immoral and should be suppressed. Human beings being what they
   are, they do a very good job of rationalizing their own fears.
   And it gets sung from the pulpit and across the dinner table,
   and heads on back to school.
6) And so it goes on from generation to generation.

Every so often, someone makes the leap that it's okay to kick the
crap out of some 'queer' on the street either because he came on
to a buddy or maybe just because he is what he is.

And make NO mistake, the 'moral authority' of certain religions who
describe view homosexuals as essentially less valuable persons, or
who declare them to be morally flawed, or who oppose them having
the same civil rights as any other members of society is part
and parcel of this evil cycle of bigotry, prejudice as well as
emotional and physical violence.

The priest or minister or imam who stands up and claims the moral
high ground on this is no different than the schoolyard bully who
beats up the kid who wears glasses or dresses different. Indeed
he's worse, because not only should he know better he's gone out
of his way to find ways to shore up his claims of superiority. He
is a conscious and willing link in the chain of hatred which has
at the end the consequences to homosexuals which run the gamut
from marginalization to mayhem and murder.

And if you think that the self-righteous types who talk about the
'sanctity' of 'one man one woman' marriage aren't willing
participants in this cycle of evil, think again. These aren't
'innocent' beliefs of the freedom of religion.

They're hatred, as surely as racism is. They're just wrapped up in
prettier packages.