Probably many of them don't fully appreciate how dishonest their arguments are. There is a sort of willfull ignorance mindset that makes it desirable to obtain the bulk of their information from only the most dis-honest and hostile of sources.
It's something akin to reasoning that one doesn't need to study Nazism to appreciate how bad of an idea it is.
Take a look at the Chick tracts that deal with biology, or the mindless crap that the Creation Research Institute, or similiar entities dispense.
I can only guess that the propagandists probably do know more of biology than those they write their literature for, if only to be able to more effectivley discredit it, but I am not certain that this is the case either.
The anti-science/anti-evolution literature seems to be purposely written to convince precisely those who have little or no education in the subjects to begin with.
I don't think that most of it was ever meant to persuade those with even a rudimentary science education.
The method seems to be to persuade those who don't know to begin with against science, and then reinforce the prejiduce, being careful to frame the points in such a way that they do not encourage real curiousity to confirm or deny the charges in and of themselves.
Then too, you can make a case that at least the leaders of the anti-science/creationist movement must be aware of their dishonesty. Those Christians, and other religious, that have been presented with accurate complete information on both biology, and their own faith, usually do not obsess about how to reconcile the two. In other words, the strict either/or argument that creationists like to make quickly breaks down with factual, unbiased education.
So, I tend to think that most creationists aren't aware of the dishonesty of their contentions, though I do think the leaders of the anti-science movement may well be.
Given my own contention that there is nothing particularly Christian about attemtping to refute and discredit science in general, or evolution in particular, and that the goals of the movement are truly political, and not spirtual in scope, I find it difficult to entertain any other scenario.