Wrong, the church's can fight among themselves on what "is" marriage. The rest of us can push this stupid issue off the table politically.
There wouldn't be a fight among the religions because they can't tell each other shite. The muslims can't really tell the christians what to believe, hell even the different denominations of christians can't tell the others what to do. The Episcopal church has pretty much said gay marriage is ok with them already.
It would be nice to get rid of it politically, but the fundies would go ape shite if you tried to eliminate marriage altogether from government.