Now that you mention that, I'm actually curious as to whether a non-Catholic couple could apply for a civil marriage license and hold the ceremony in a Catholic Church...I don't think the local diocese would allow that to happen in their building, since we generally reserve them for sacramental (religious) ceremonies, but you've piqued my curiosity. I do think my example is still pretty good, since the couple in your rebuttal chose to go to a Catholic building instead of a more open venue. The choice of going to a place that you specifically disagree with was all I was trying to highlight.
Also, since you brought up the notion of choice, could you please enlighten me then on why some people decide to change their sexuality? Why is it seemingly immutable for some and yet others do decide to be straight, or switch from being straight to gay, and yet definitely deny being bi or pan. I've always been curious about that.
Please note that I'm not trying to be rude, silence, or aggravate you with either of my paragraphs, I'm just furthering the conversation for the sake of my own enlightenment. It'd be hypocritical of me, in light of my above comments, to specifically go to a place whose values I somewhat disagree with (this stream) and try to force you 'round to my way of thinking. :)