The perception that public prayer or public religious speech is "free advertising" says more about your attitude towards people of faith than anything else. I guess you're all for free speech unless it's religious in nature. The left is full of your kind.
Ah, insults. Better than honest debate, eh?
You cannot deny that allowing one religious group to speak in a public forum grants a certain ligitimacy or prestige upon it, can you? And if that's granted to one, is it right to deny it to others just because the others don't share your personal faith?