Theory or no, it certainly is an EXPLANATION for a current area of ignorance.
So is claiming that my cat created the universe and all in it Last Thursday. That doesn't mean that it should be presented as a viable scientific alternative.
Exactly. Not all explanations are equally valid. That's why we deal in theories.
Words mean things. ID isn't a "theory" in the scientific meaning of the word. There are no alternative notions that get anywhere close to fufilling the basic requirements for a scientific theory, which is why evolution is the only one worth talking about in science classes.
We are talking about the origin of life now - hello - is that not a part of life sciences? Just because we don't know the origin of life, we can't act like life has no origin. Since science, in everybody and their mother's words, can't explain the origin of life - are we supposed to just say "O, never mind"?
Mentioning creation or a Creator is not illogical.