Response to Catholic Billboard In Massachusetts Defaced:
The difference being, Catholicism is a choice, a chosen lifestyle. This billboard is trying to sway people into changing an opinion that they have about god (assuming that they have chosen not to be religious). Changing an opinion cannot be considered anywhere near something like promoting same sex marriage, which is defending the civil rights of a minority that has been oppressed in our society. Defending an opinion and defending the civil rights of a person born into a minority are not equally important.