Saying that the status quo should be maintained is a terrible justification for saying something is right or wrong. There are a number of events the USA has done in its past which we now can pretty clearly say were terrible practices. The country is similar to a child growing over time, the things that seemed right as an inexperienced youth no longer seem right as an experienced adult. just because we felt it was ok to ignore the liberties of non-christian minorities once upon a time doesn't mean it is okay to continue that practice for all time.
As an atheist, I don't see what benefit opening with a prayer provides to a non-denominational decision. On the other hand, if I were there to speak on behalf of a homosexual cause, I would certainly feel discouraged by a public discourse which begins with a prayer from a religion which is openly against homosexuality.
