(some) scientists pay them attention because they perceive them as a (social) challenge

I think that this is enough to explain everything that we see. This is not evidence against their effectiveness, but that's my null hypothesis.

I think that it's telling that when the ACLU wanted to challenge the TN law against teaching evolution, they chose Scopes, whose school district had assigned him a book containing evolution. The creationists, and perhaps their opponents, cared more about the nominal law than the facts on the ground. But when Scopes challenged them by asking his students to turn him, they had to prosecute.

(I certainly agree that they lie; I'm just skeptical that they're particularly effective lies. I think it's better modeled as selecting people who are better at lying to themselves than people who think about what lies are effective.)