The point of view from proponents of ID might be; "if the Big Bang, which is simply a theory is shoved down people's throats - then why shouldn't this be mentioned as an alternative?".
To an extent I agree with that, but I wouldn't put it in the classroom as it won't help anyone. If you have an open mind in the first place you'll take things from all points of view, so...
Anyhow, my 2p.