What is a church for if not public prayer? And you're welcome to pray in any place where no one is constrained to listen. However, if I am trying to participate in democracy by attending a meeting, there is no reason for religion to be involved. The same at a public school graduation. I am there for the ceremony, not to participate in prayer or be forced to listen to a sermon. If you are standing in a public park praying aloud I might find you annoying, but can walk on by. If it's at a council meeting I shouldn't have to choose between listening to religious petitions and walking out. And what is the point of "public" prayer in the first place other than to impose your beliefs on others?