No matter what 'everyone' says homosexual marriage is an abomination. The issue boils down to official recognition and granting of special status to a lifestyle which condones sexual relations of an illicit nature. Anyone who believes that this is not a big deal must be denying history. As Edu posted earlier one of the main reasons for the flood of Noach was due to sexual immorality. The next step on this ladder is legalizing sexual relations between man and animal {as is what also happened in Noachs times}.
One of the major traits which a Holy Human being exhibits is sexual morality. This is one reason our forefather Joseph was called a Tzadik {Righteous Man} was due to his modest and resistance against the advances of his master Potiphars wife. It is important to realize that one of the reasons that Hashem makes his covenant with the Jews through the Brit/Circumcision is to remind the Jew that his sexual organ also should be considered Holy, and should only be used for holy reasons.
I will never accept a marriage between two people of the same sex. If they refer to their 'marriage' I will refer to it is an illicit relationship. Or I will use the 'scare-quotes' with my fingers. As Dr Evil did in Austin Powers:
'Marriage' No amount of 'reprogramming' or 'doubletalk' will convince me otherwise...