Really? the article you linked says the opposite of what you claim:
Today many Christian denominations regard marriage as a sacrament, a sacred institution, or a covenant, but this wasn't the case before marriage was officially recognized as a sacrament at the 1184 Council of Verona. Before then, no specific ritual was prescribed for celebrating a marriage: "Marriage vows did not have to be exchanged in a church, nor was a priest's presence required. A couple could exchange consent anywhere, anytime."
Jewish and Muslim Marriages are fine, they are all the same religion.
I'm not sure a lot of Jews and Muslims would agree to that classification, but sure, they're all descended from the same god. But I guess that means Buddhists and Hindu are barred from marriage, instead?
Atheists don't need to get married as they can get a civil union, and that is what you get when you stand in front of a judge and say I do.
Actually, it doesn't actually matter who you stand in front of, what you get is a marriage when you sign the piece of paper that the government issued you. You can go in front of a priest and say your vows, but if you don't sign the paper you're not married. Priests get no say in who marries and who doesn't, they can only choose to perform or refuse to perform a ceremony (of course, in so far as they own private property they are also allowed to deny use of such space for the same purposes).
The government needs to stop trying to control every damn thing.
Frankly, maintaining the registry of people who are legally married seems like exactly what the government should be doing. Maybe you want the damn government to keep it's hands off the legal system too?
Marriage comes from religion, the word originated in Latin, the language of the Catholic church to describe a ceremony that they performed called Holy Matrimony. If you don't like that it originates in the Catholic church, invent your own damn word for it.
Except you are 100% wrong, marriage predates the concept of Holy Matrimony which was introduced as a Catholic sacrament in 1184, we know that the earliest recorded marriage contracts are from around 660 BC. So that's over 1,800 years before it was associated with Christianity.
If another religious denomination wants to marry a homosexual couple, good on them.
Then we are agreed, the government should not be enforcing a ban on same-sex marriages. Whether it's because you believe that everyone should be treated equally or because you don't think the government should be preventing the Episcopalians, the Unitarians, the Anglicans, and the Presbyterians (among many others) from performing same sex marriages, the end result is the same.