As long as one understands that ID is a traveling medicine show, it makes perfect sense. Nobody asks why the patent-medicine dealer didn’t, if his claims were true, have them validated by testing for safety and efficacy. Nor does anyone ask why he didn’t issue a disclaimer indicating that these claims had not been validated by testing.
I think the core thing here is that not only is ID dishonest, but ID is driven entirely by non-biological interests. With rare exceptions, ID supporters are not the slightest bit interested in biology, so their curiosity about how to work out the details, or substantiate the claims, is very limited. They’re interested in the culture-war implications: how to get creationism back in the schools. For them, if it sounds vaguely science-y and kicks Darwin in the pants, that’s all they need. And it is fair to say that they are already well accustomed to believing things on inadequate, or even entirely absent, evidence, so this requires no special change of mental habits.