The failure of the theory you pose lies in the belief that marriage is and always has been nothing more than a religious rite. Long before Judeo/Christian practices appeared in society the so called institution of marriage existed. It is not some sort of exclusively religious rite but a civil contract.
However, every time the anti-equality forces rise to contest same sex marriage one quickly finds that behind all their rhetoric and unfounded assertions resides the shadow of religious intolerance. Not simply content to follow their own dogma and subjective dictates these groups actively work to enshrine in law the foundation of their religion while at the same time defending their abhorrent acceptance of discrimination.
Too often when these anti-equality groups are called out on their religiously fueled opposition to civil law and rights they choose to play the discrimination card themselves. The flood society with false accusations that those who do not agree with their active efforts and doctrine of trying to take away their religious freedom.
No matter what your religion says you should not have the right to demand I abide by your beliefs. Nor should society allow you the ability to enshrine in history the idea that others that do not subscribe to you ideology and may differ in composition from you are a lesser entity.
Marriage and its so called definition have constantly been in a state of flux do to the evolution of civilization. To demand that suddenly it stop being fluid simply because it has reached a composition that encompasses you and serves your beliefs is paramount to using the “I’m aboard now pull up the ladder” sea rescue mentality. In other words it is a failing argument and all that advocate its use know that. They use it because fear and a designed program of repeated misinformation promote confusion, which usually benefits the status quo in this case their false assertions.
Marriage equality will be the law of the land it is not a matter of if but of when. In the end society will toss off the yoke of discrimination and laws based in religious ideology and accept equality for all.
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