Imagine you are a young red-stater. You go to church every week, have grown up believing in your god and your parents religion. Other ideas are not intrusive on your daily life or routine. You are never exposed to any other points of view. These days, unless you go to an increasingly unaffordable college and take a philosophy course or a comparative religion course, you can go your whole life in Red State America without ever getting out of your philosophical comfort zone. Then, suddenly, in high school, you have access to a course where you can learn about Intelligent Design. But, you are learning it in the context of questions like "Does God Exist?" And you are learning about your religion in the context of other world religions whose beliefs are given equal time and weight (and as an added bonus, upcoming generations of Americans will have a much broader, firmer understanding of Islam than we do today...).
Can you even begin to fathom what this new philosophical diversity in our schools will do to fundamentalistic worldviews? Their ideas will be undermined simply by the fact that other religions are given equal weight and credence. Ideas about Intelligent Design taught along with debate on philosophical questions like "Does God Exist?" will undermine what fundies have been indoctrinated in their whole lives: an unquestioning belief in the existence of their particular deity and the truth of their particular creed. Knowledge of other religions promotes tolerance for other viewpoints and undermines the fundamentalists belief that their faith is the one and only true faith. Thus, by proposing Intelligent Design, fundies will in essence be sowing the seeds of their own world-view's destruction.