Your thesis is very weak.
Gay Marriage should be legal because gay couples should have the same rights and freedoms as anybody else
"Gay marriage" isn't legal or illegal because in the majority of the US, there is no such thing. Marriage, as defined in many statutes, is a legal partnership between two people of the opposite gender. There is nothing about "two people" or "a couple." Furthermore, gay people have the same legal rights and freedoms as everyone else under the law. They are free to marry people of the opposite gender and have a marriage like everyone else in the world, with the same benefits and responsibilities. The problem is, they don't want this. Your thesis is therefore meaningless from the beginning.
What you
should be arguing is that perhaps the legal definition of marriage should be
expanded to include unions between members of the same sex because you think these couples should enjoy the same legal status as traditional couples.
The other alternative is to create a parallel institution for them, granting them all the same legal duties and rights of marriage.
Talking about whether or not gay marriage should be legal, however, is absurd.
we live in America so nobody should be told who they can and cannot love
That argument has two problems with it. The first is that the law (which you are arguing about) doesn't prevent gays from loving each other in any part of the US (esp. after Lawrence v. Texas). The only bans on intimate relationships in the US apply to incestual relationships, relationships involving people not of age, and some relationships where there is an "imbalance of power." Remember, you're asking for legal recognition of gay relationships, not asking for them to be allowed. They are allowed already.
Secondly, it's cheap, patriotic, American propaganda bullshit. This country has very little regard for personal freedom. The "land of the free" is no such thing. Our constitutional rights have been twisted around by the courts so many times, they're meaningless now. And those are only the enumerated ones. Many other personal freedoms have been eliminated. Saying that we should have freedom because we're in America is not much of an argument.
