"...nor shall any State deprive any person of life, liberty, or property, without due process of the law; nor deny to any person within its jurisdiction the equal protection of the laws."
That basically means that a state can not deny a person their life, liberty, or property without a really damn good reason. Pay attention to that part 'cause it's important later.
Let's take a look at that liberty bit for a second. A quick search on Wolfram Alpha gives us a few definitions, one of which is:
"personal freedom from servitude or confinement or oppression"
Freedom from oppression.
"Oppression: the state of being subject to unjust treatment or control"
Today in this country, you have the liberty to vote for your leadership if you so desire. It does not matter if when you were born you had two X chromosomes or and X and a Y chromosome. You only need be a citizen (That citizenship bit gets murky but CGP Grey explains it better). In the United States a citizen has the personal freedom from servitude or confinement or oppression to vote on the political candidate of their choosing. The States cannot bar someone from doing this without a really damn good reason.
How did we go from Marriage Equality to voting rights? It's called an analogy. A man with dark skin has the right to vote just the same as he has to marry a woman with light colored skin. That same woman also has the right to vote. A woman with Republican beliefs can marry a man with Democratic views. Heck we even let Muslims marry Atheists. Lesbians can vote. Why can't they marry? Before you answer!
"Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof..."
Top that off with, who's to say the God I worship doesn't forbid same sex marriage? Why does the God described in the King James version of the Bible (henceforth known as KJB) get precedence over all the others? We let Hindu's marry, they have a bunch of Gods. KJB says theirs is the only one, why aren't you guys pissed at them? Heck L. Ron Hubbard flat out made up a religion and people don't question those guys (mostly). In fact, I'm making up my own religion right now: The Church of the Rainbow Unicorn Brotherhood/Sisterhood (trademark pending). The holy text is a somewhat used napkin that I found on the counter, written on by me, from knowledge imparted to me from the Great Father Unicorn. It says same sex marriage is allowed. Right above that, don't be a dick.
Dispute that.
The fact of the matter is, marriage is an institution managed by the laws of the States that make up our Union, and as States they should not be allowed to prefer (or discriminate against) one type of marriage over another. If you don't like it - too bad. Your argument is about as valid as a white man saying women and black people shouldn't be allowed to vote. It's discriminatory and not equal.
The other option would be to remove all legally binding aspects of marriage (including all of the benefits, we can't be discriminatory now) and leave it all up to each religion, but just know that The Church of the Rainbow Unicorn Brotherhood/Sisterhood will be right there too (as afforded by our Heavenly Father Unicorn and the First Amendment of the Constitution of the United States).
