Everyone has a right to their opinion based on their own religious or non religious reasons. However, creationism and intelligent design are fundamentally based on religion.
If a school decides to enforce creationism or ID, it should only be offered as an elective theology class and not inserted into any of the life science classes. This would still allow the controversy to be taught and could allow creationism/ID to be taught more in depth and in a more direct fashion in public schools.