To avoid the freedom of religion/freedom from religion arguments, I think that the major thing I have a problem with on things like this is that people have the freedom to worship how they choose, or not worship if they so choose. But this doesn't mean that they have the rights to repress the public expression of someone else's religion. Freedom isn't allowing people to express views that you agree with, but allowing them to express views that you disagree with. Just because someone disagree with Christians, doesn't mean that they have the freedom to never see or hear anything anywhere having to do with Christianity.