I'm not dense. It's the word "right" that I don't get.
And the exclamation point.
Call me overly symantic here, but I associate the word "right" with a level of inappropriate political zeal - such as the NRA and the whole "right to bear arms" and form a militia. It's a limiting word of separation.
For instance, the current thinking of the CDC on a public health care system is that it's not a right (like our current system of expensive private insurance), but a privilege - meaning that everyone deserves it not just those who have the "right" to it in the form of cash.
So whenever I see that sign, all I see is a weird mixed message. I guess something like "Civil marriage is something everyone deserves" would make more sense to me. It sounds much more open and welcoming than the current sign.
-e