My understand of this move in many schools, it that highly religious (and highly un-American) Christian parents don't want their children getting dressed up for a pagan event. What a shame that they're ruining it for everybody else.

i was born and raised Catholic. I celebrated Halloween since i was an infant. Simple thing people. If you don't like it, don't follow it/practice it. Don't ruin it for everyone else. I have the same views on other topics too (i.e. same sex marriages, but that's a completely different topic). No one is taking their rights away to practice their religion how they want to, so why should 'our' rights be taken away. Kids get to pretend they are something else. Its dress up! Every kid does it at one point in their lives. Whether it be a princess, a super hero, doctor, whatever, it's something fun for the kids to do. Let them be kids while they still can!