Only parochial schools are allowed, by law, to teach religion in any form. Whether it is the religion it's self or the history and/or customs of said religion.
No public school is allowed to teach the customs, history or actual beliefs of Christianity. Public schools are not allowed to teach religion at all. The crosses the line of separation of Church and State.
Teaching religion or the tolerance of any religion should be in the home. NOT the schools.
Ban all courses and teaching material pertaining to Islam from the public school systems immediately.