You don’t go to high school biology class to learn particular facts; you go to understand the general framework of evolutionary theory. Rather than contradicting any single fact, Intelligent Design undermines the entire intellectual basis of biology.
The central message of evolutionary theory is that complexity emerges spontaneously through purely natural processes. This is a difficult truth to grasp, and it flies in the face of centuries of cultural tradition. The Biblical narrative says that the world was created especially for humans, and that we’re the most important thing in it. Evolution says that the world came into being as a series of contingent accidents, and that humans are no more special or important than slime molds or wolverines or ferns or sea cucumbers (and that we’re much more like these creatures than unlike them.) If your science teacher tells you that a magical force is guiding evolution, you’re being let off the intellectual hook. Rather than having to struggle with the counterintuitive idea of self-assembling molecules, you’re comforted by a thought-terminating fantasy.
We’re at a critical juncture in technological history. It won’t be long before we can just print out DNA sequences at will to create custom organisms. If kids are coming out of American schools thinking that biology is being guided by a magical force with intentionality, that’s going to be a severe intellectual handicap. It isn’t just scientists who need to understand these things. Ordinary people will need to vote for policymakers who regulate and fund biotechnology, and will need to vote with their dollars and opinions as to whether the products of biotech take hold. We’ll need to understand that the line between “natural” and “artificial” is, well, artificial, that living things are made of the same molecules as everything else, following the same physical rules. We’ll need to understand the profound similarities between biological viruses, computer viruses and our own self-assembling nanobots. We’ll need to know that humans are part of nature and not separate from it, and that evolution is mindless and difficult to predict. I shudder to imagine the intellectual damage that ID does in such a world.