ID is based on opinions. "I think everything is perfect, I don't think all this perfectness could be the result of chance or nature. I think it must have been an intelligent creature. I think it must have been God."
These opinions can hardly be supported by facts, that is the big problem ID has. Is it a fact that our backs or eyes are bad or perfect? No, that is a matter of opinion. Is it a fact that earth couldn't have been created by chance? No, even this is just an opinion.
This is even the cause of the problem tuppence mentioned, because how can you argue about opinions? Since we humans like to argue we argue about opinions anyway, without much succes.
Evolution is trying to work based on the facts, even if this perhaps hardly works because there aren't that many facts and our understanding might not be the best with those few facts we have. But it is building on facts, it is just still under construction and will be under construction for a long time.
If you make me choose between something under construction based on facts or something based on opinions but finished, then I will choose for the facts.
If you make me choose what to teach our kids, then I will say both, because there is no way to know which one is true.