Why the fear over Creationism in schools?

yea, i don't understand why people can not hear both sides of it. i have no problem with world religion being taught in schools. no one is being forced..its just teaching about other peoples belief systems around the world. if you just teach kids ONE thing..that is being narrow minded..you also have to teach kids that no everyone is going to have the same belief and think like they do. nothing wrong with going outside of the box.