Actually when I was in school we had a section in social studies that discussed religions and we read many excerpts from many different texts. However, that being said, after hearing lots and lots of people on this very site remind me again and again and again that Mormans are a cult and aren’t really Christian, I know that some people are so blinded by their own “rightness” that it wouldn’t stop with just passing out Bibles or Korans to interested students. Further your definition of “filth” would surely be disputed in court which means lot of money coming from school budgets going to lawyers instead of teachers. It’s such an easy thing to just let Bibles be passed out outside of school grounds. I think the consequences of NOT doing this could and most assuredly would be far worse. You have to ask where does it end and it’s not too hard to see where this will end up in a country where anybody can and will sue anybody over anything.
Unfortunately, they're right and you're not. The Mormons do NOT believe in the Trinitarian God-head, which is a central tenet of Christianity.