I think there are some people who are predisposed to homosexuality, some very strongly predisposed. I think others are not strongly predisposed to being either straight or gay. I imagine there is a whole spectrum of sexual disposition and not a gay/straight switch in our DNA.
I'm 100% with you that it does not matter if it is a choice or not. The individual has every right to make that choice if that's what it is. I find the "can't help it" argument to be weak as well. To me it's completely besides the point. If you were "born that way" fine. If you chose to be that way, fine. Both are legitimate and both individuals deserve equal rights under the law.
Did I miss something? When has he ever said that it doesn't matter if it's a choice or not. He has blatantly stated that it IS a choice. I also haven't seen him mention anything about being treated equally in the eyes of the law. I'm too lazy to go back and check, but I'm pretty sure you're confusing him with someone else who has a brain.