I, for the thousandth time, have to disagree with you. There's no rights or benefits that a gay couple will be denied by going through a civil union rather than a marriage, so what's the headlong push for marriage all about? The push for gay marriage has nothing to do with the stated purposes - that being equal access to loved ones in hospitals, insurance, etc. There isn't a hospital in the country these days that would deny a gay couple access to one another, and most insurance companies already allow for designating "life partners" as beneficiaries or to be on policies. The push for gay marriages is 100% about legitimizing the gay lifestyle.
The gays have largely legitimized themselves with the public, the media, and with the government. They have one last roadblock and that's the churches. As long as churches, and the people who attend them, see them as being morally objectionable, the gays can't be legitimate. So how can the gays get past this roadblock? The only way is if they can get the government and the courts to help them, and the only way they can do that is by making gay marriages the law of the land. Once the government determines that gays can marry, the gays will immediately start suing the churches, as public places, to allow them to marry. The churches will then have to either accept gays, close themselves to members only, or go broke from fighting the lawsuits. Don't think it'll happen? Look at all the legal heat the Boy Scouts took because they banned gay scout masters.
As an Agnostic I have no loyalties to any church, and don't really care about anyone's religious beliefs. But over the past 20 years we've seen assault after assault on the beliefs of those who do hold them by the ACLU, pornographers, etc. The Founding Fathers designed our government in such a way as to avoid a repeat of the Church of England experience. It was King Henry VIII's insistence that the laws of the Roman Catholic Church regarding divorice be changed that led to the creation of the Church of England, and hence the establishment clause ensured that the United States government could not make any laws effecting church laws and could not go out and form a new religion like King Henry did if they couldn't get the churches to change the laws. But that was a couple hundred years ago, and people now believe that the establishment clause is in place to protect government from religion instead of the other way around. I see legalizing gay marriage as the start of a constitutional crisis the likes of which we haven't ever seen, and we don't need that as a country.