Basic common sense, decency and manners would inform the Baptists that it is a CATHOLIC festival and they are guests at the festival.
If the Baptists want a Baptist festival, have one! If the city disallows it, sue them.
Christians act like socially retarded, amoral humanist radicals now.
Don't you mean some Christians act like socially retarded, amoral humanist radicals now? I would even say that "some" is a very small minority. Genuine, spirit-filled, Christ-centered believers would know the proper way to act and would act properly.