[sageb1]

"In fairness, I think many Christian churches would also object to such ads being posted in the immediate vicinity of their houses of worship."

You're right, but I am not required to be fair.

[Libertina]

Christian churches would object, but they'd be laughed at, attacked in the media for being "against free speech", picketed, and in the end a half dozen more posters would go up to "teach those religious extremist bigots a lesson." Unfortunately, the church would probably respond by keeping its profile low. And inside the church some of the good Christians would begin to argue with each other about being more "tolerant", reaching out, etc... ad nauseum. In the end an apology - to the perpetrators.