I would ask what is the next move of the atheists? Are they going to start teaching multiverse stuff? An unobservable, improvable, wild speculation - the only one they have to counteract the "fine tuning" problem?
ID has more answers for the kiddos than science has been able to provide.
You make it sound like all theists want ID taught in school. There are many theists that uphold the idea of separation of church and state and would be appalled if religion was brought into public schools (more so than it already is).
If a class did teach about multiverse theory, it would teach about what the theory is and why... not pushing it as if it is fact. There is nothing wrong with teaching scientific theories.
ID is a very simple answer and that is what most people want; they don't want to have to think about things. I could you 10 great books that describe evolution in detail, the universe, the Big Bang Theory, etc. or we can scrap all that and just say "God did it" -- tough choice huh?
ID was our first attempt at philosophy, and because it is our first attempt... it is no surprise that it is a horrible one as well.