I considered calling the police and reporting it as hate speech, but ultimately decided not to. Although I found it highly offensive, I also recognize that other people have a right to speak their minds (and make themselves look like asses). I may strongly disagree with the message, but I firmly believe in their right to express it ...
I take comfort from the fact that it wasn't generally received well (there were quite a number of people clustered around it, some of whom wrote pro-marriage messages over the anti-marriage ones). But the fact that anyone could think this at all ... *sigh*.
It just makes me realize how far we have left to go, especially in the Human Wasteland. :p