Yeah, I think creationists are wrong, but what harm do they do?
Education?
Even in the worst case scenario, where evolution was not taught in public schools and only YEC was, what real impact would it have on anything?
Stupid children?
An entire generation of scientifically illiterate children? The continued refusal to accept scientific consensus?
The idea that a "continued refusal to accept scientific consensus" is in itself a bad thing shows just how scientifically illiterate people can be.
Really, there are plenty of kids who have never learned a thing about creationism whose knowledge of evolutionary processes are mostly informed by Pikachu.
Pikachu isn't being taught in schools.