Where did you get that idea? Intelligent design assumes God intelligently created an intelligible universe, and created intelligent beings to observe it. So, as intelligent beings do science, they find evidence of intelligent design everywhere.
Some (namely those whose voices and words you would have outlawed in public schools) happen to take it as a given, and use the disciplines of science to ascertain in more detail how God did what He did and does what He does. The fact that certain creatures have the capacity to adapt to their environment (evolution) points to intelligent design. Every instance of organized matter performing specific functions points to intelligent design.
A fundamental difference between evolutionists and creationists is the ultimate cause of this organization of matter and the overall presence of an objective reality available to science on an intelligible basis. Some prefer to call it "nature." Others prefer to call it "God." To say the presence of organized matter that performs specific functions MIGHT be best explained by intelligent design is merely an overall, tentative summary based upon deduction.
Your protestations to the contrary evidence that your concern is not science, but theology and pholosophy. Otherwise you'd keep your nose to the science grindstone and keep your mouth shut.