sure, you can commit to religion, but you can also opt out of it and no one will really care. Marriage is something everyone notices in terms of breaking up and divorcing. Also, while both are ties to one another, religion is something many people to not have even if they are married.
While religion and marriage have some similar attributes, they are different. There are different types of marriage, and marriage can happen without any religious context at all. There is sacramental marriage, which obviously requires religion. There are many different types of religion as well, and while the two institutions can intersect, they are different.
Marriage may have religious implications in the ceremonies privately performed, but marriage is also a civil institution. It is something that requires paperwork, and the result is a change in legal status between the two people getting hitched. For this reason, you have to consider the institution of marriage as a function of the law independent of religion.
I do not believe religion and marriage are one in the same at all. Religion can mean a lot of different things to a lot of different people, but in a general sense its a mode of belief usually attributed to believing in a higher power. Marriage is the union between two people who love each other and have the intention of being together for the rest of their lives. The two are not comparable.
No, I do not believe that religion and marriage are one in the same. Marriage is belief and a union of two and sometimes more, people. Marriage does not necessarily have to tie into religion. Many people try to tie them into each other, but they should be kept separate and maintained in different categories.