If 2 atheists can get married at the court house, how is marriage a religious institution?

To all other answerers:

Marriage, as an institution transcends religion. Marriage is more of a contract between two individuals that brings with it, a certain number of rights and privileges that protect both parties in the marriage, and the child borne from it. It's wrong to say that Marriage has got anything to do with religion...especially in a democratic secular country.

Personally, I think it is the one thing both theists and atheists agree upon :).

It is in the church, but not in government. That's where all the arguing over marriage-equality and "keeping marriage between a man and a woman" comes in. Religious people think marriage is one thing, non-religious people think it's another. In reality, it's both.

It would be like if the government starting giving tax breaks for children who got baptized. Once it became the norm and everyone was baptizing their children, religious or not, would that really be religion anymore? Or a secular part of government? Or both?

Marriage is both a religious and secular institution. On the one hand, marriage in the religious sense is officiated by a pastor and reflects commitment in the eyes of whatever particular deity one happens to worship. On the other, marriage in the legal sense confers certain rights on the couple. Christians have to go to the courthouse too, you know.

It's not. Religions just want to claim it, even though marriage existed before any religion ever did. Even gay marriage existed before Christianity.

Besides, marriage, at least as far as the government is concerned, is a contract with legal benefits and tax breaks for the parties, the whole 'religious' aspect of marriage that people claim is purely from their personal religion and holds no substance anywhere except their church.

a magistrate isn't a ordained minister.the same as a ships captain. so why would a atheist want to be married under a religious institution

It's not unless you get married in a church or other religious place.

Marriage has always meant the union of opposites. You can't marry two bolts or two nuts...except maybe in your world. The term marriage was specifically created to define a specific type human relationship, just as other terms define other relationships.

I think the more appropriate question is why would 2 atheists get married when the history of marriage is steeped in religion.

Checkmate.