Christians arrested outside Arab festival in Dearborn (for preaching the Gospel): http://www.christianexaminer.com/Articles/Articles%20Jul10/Art_Jul10_01.html
Christian ministers arrested for praying near gay festival: http://www.lifesitenews.com/news/archive/ldn/2007/jul/07071001
In each case the charge was “disorderly conduct.” So praying and discussing the gospel outside the events of certain (protected) groups is “disorderly conduct,” but going to military funerals and screaming “Thank God for dead soldiers” at the bereaved is “protected speech.”
That’s how it works, it appears.