So instead of just using the word marriage for something that IS a marriage, we have to invent another term that doesn't mean anything else than marriage, but of two people who are of the same sex. Just because we have to. And that isn't petty.
I've seen many things described as a marriage. Like special diplomatic relations between countries, business mergers, even product announcements. And I think that people can understand this. Once again, try to describe civil partnerships to somebody. What are you going to do? Say 'It's like a marriage, just don't call it so, because I don't like it'
(In the same way, I'd even describe your reason as 'religious, just there are no gods and churches and other deities involved'. We are also used to call fanboy disputes between the text editors or operating systems as religious wars. And it's a very good description.)
That's exclusive, not inclusive 'us', I believe. This thing isn't serving me well. In fact, it is serving me very badly (gay marriage isn't going to improve that very much, though any remedy is welcome).
