Many of the devout religious view any "civil" marriage, i.e. a union that was not sanctified by a church, as illegitimate, but that's their religious preference and not something they get to legislate via the government. So? That's a normal & commonly accepted practice. Same-sex marriage is both pointless and groundless. It has no history of long use or genuine place in society. It is a special privilege invented for the benefit of the few, and attempts to legally ratify it are attempts to force every one to conform to their view. It is no different than attempting to govern according to the Bible.

1) It has no history because homosexuality has historically been forbidden and/or persecuted by governments (usually "high-minded" religious politicians). Thus, your argument on that point falls apart because the world (or in this case the nation) is in a unique position to finally extend the right of recognized union to homosexuals for the first time.

2) It would not be pointless if you are of the persuasion that certain tax benefits are gained through marriage for the sake of having children. I do not know whether you support this theory or not, but for those who do argue this direction then gay marriage would provide the same benefits given that the gay couple adopt. My own response to such people who argue against gay marriage by using this '"incentive to procreate" argument is that if the theory were true then such benefits should be taken from heterosexual couples who don't have children in a reasonable amount of time (naturally or by many of the same methods gays could use). If you do not subscribe to the "incentive" theory then ignore this.

3) "...attempts to force every one to conform to their view". You know this describes every law, right?