From a totally objective standpoint, is it not any more unfair for someone who, in this example, believes in gay marriage to force their views upon someone who disagrees, by way of laws?
Sadly, you are correct. This is a country where you are allowed to hold your own personal viewpoint on any matter, even gay marriage.
There will always be people who oppose gay marriage. There's no doubt in that. People who are for gay marriage draw the line at actively banning gay marriage, before it became allowed in the US, and actively passing laws that limit what publicly gay (I seriously have no idea what the proper term is) can do or in some states you can be fired for being gay. Though I imagine these are the same states who'll fire someone for being non white under a blanket offense.
I'm personally fine if you oppose gay marriage. I'd be a bit annoyed if you said you wanted to kill the gays or pass laws so they can't adopt, buy a house, be able to fire them based on their sexuality, among others things.