Does it not depend how one views marriage?
In the US there are a couple distinctions that are clear.
There is an explicit separation between state and church. There are, in fact, two kinds of marriage - a secular contract and a religious rite.
So it makes sense to be clear which marriage you are talking about - the secular or the religious.
Certainly a religion can define the rite, the rights, and the responsibilities that are associated with their particular religious marriage when a couple is interacting within their religious community (right or wrong, it is self-contained within their community). We all know, for example, that Catholics aren't required to view a particular marriage as a valid religious arrangement if not performed within the rites of the church. The separation between state and church protects Catholics from needing to acknowledge, within their institutions, that a marriage is valid. Living in sin? No eucharist for you.
But Catholics - or any religious - cannot deny the secular benefits and obligations of a couple when that couple is engaged in the secular contract of marriage. Catholics cannot deny married Jews their rights and responsibilities outside of the Catholic institution. Catholics cannot prevent married Muslims from benefitting from Health Insurance opportunities simply because the Muslims didn't have a "church wedding". Catholics cannot stop married Buddhists from visiting their spouses in the hospital. Catholics cannot tell Baptists which tax form to use because of the particular religious rite they may have used in addition to obtaining a legal marriage certificate.
When religions want to step outside and start playing in the secular world, doing secular things, offering services to the world outside their religious community, they need to be ecumenical in their treatment of those they serve.
You may have a particular view of "marriage" - and within your religious community, you are free to hold that view. But step outside of your community into the larger world where there are other religious, and you must contend with the secular definition, a great unifying, leveling and equalizing mechanism that provides FREEDOM in the US.
Without the freedom to engage in the religious rite of your choosing - or no religious rite at all - their is no freedom of religion. The equality of the secular in dealing with secular matters trumps individual religious viewpoint.
I have no qualms with the distinction between religious marriage and secular marriage. I have no interest in meddling or engaging with any particular religious rite.
I have great concern that the secular contract of marriage remain free of control of any one religion. The separation of state and church is important. Otherwise, we may as well be living under the theocracy of the WTS - or Islam.
Or Westboro.
Imagine a WTS-led government telling you no oral sex.
Or a Westboro-led government telling you no gay sex.
There's really little difference. It's better, IMO, to give more freedoms in this case than allow others to strip away too much.