More importantly, in the true spirit of democracy, free speech and freedom of religion, let everyone put up a display and let the public enjoy, embrace or ignore each of them...any restriction is offensive to everyone except the liberal atheists...and if they had any real brains, they would come up with some twisted graphic version of gayism, abortionism, liberalism, evolotionism, communism, environmentalism, etc. except that they all are behind DENIALISM OF THE FACTS OF LIFE!
I'm sure they have tried just that. Places like San Francisco may well be overrun with obnoxious liberals who want to offend the rest of the country. See where it gets them.
The "true spirit of democracy" doesn't give anyone 15 seconds on the "public megaphone" because the concept is hopelessly ridiculous. I remember hearing some kid from some Benelux/Scandinavian country gushing with perfect sincerity about the moral superiority of his country for giving a neo-nazi party a free 15 minutes of airtime on their public/quasi-public television network before an election. That's rubbish (and probably disingenuous to boot).