Then move to somewhere more progressive.. or crowded. The point IS that if you REALLY wanted to, you could go to one. Drive. You're splitting hairs over a hypothetical situation.
The problem is that civil unions and marriage are not synonymous. Straight people can have a civil union OR a marriage. Gay people can only have a civil union. That's not equality. Your argument would *sort* of be alright IF we made it illegal for straight people to have civil unions. That's not going to happen, and even if it was thinkable, I wouldn't want to limit the freedom of another person.