Update: came across this video which seems very relevant to this post. It is a quick (ten minute) video that discusses whether or not people are actually open minded.
Here is a short piece that explains why bad arguments persist.
...there’s a certain class of rhetoric I’m going to call the “one way hash” argument. Most modern cryptographic systems in wide use are based on a certain mathematical asymmetry: You can multiply a couple of large prime numbers much (much, much, much, much) more quickly than you can factor the product back into primes. Certain bad arguments work the same way—skim online debates between biologists and earnest ID afficionados armed with talking points if you want a few examples:
The talking point on one side is just complex enough that it’s both intelligible—even somewhat intuitive—to the layman and sounds as though it might qualify as some kind of insight. (If it seems too obvious, perhaps paradoxically, we’ll tend to assume everyone on the other side thought of it themselves and had some good reason to reject it.) The rebuttal, by contrast, may require explaining a whole series of preliminary concepts before it’s really possible to explain why the talking point is wrong. So the setup is “snappy, intuitively appealing argument without obvious problems” vs. “rebuttal I probably don’t have time to read, let alone analyze closely.”
A classic example of this theory in practice is the absurd 'watchmaker' argument. It goes as thus: a person stumbles across a watch, a fantastically complex device. Obviously, there was a creator of the watch; the pieces couldn't have accidentally happened together by chance. To a layperson, that sounds intuitive. Now any biologist will tell you that evolution doesn't work that way, but explaining precisely why to a layperson is going to take multiple steps and they'll probably have ceased paying attention by that point. And thus bad arguments persist, and there are people who don't believe in evolution. Going further, creationists can be neatly placed in one of three categories:
1. People who simply do not have the mental capacity to comprehend the theory of evolution. This would include small children and people with mental disorders.
2. People who are insufficiently educated about the concepts involved, or just don't care all that much. This is by far the largest percentage. They may be creationists because they were raised by creationists, or work with creationists, or because their friends are creationists. These people may also erroneously believe that they are forced to choose between God and evolution...in truth, evolution is easily reconciled with religious belief.
The curious thing is that you would have expected this group of people to have gradually diminished, just like I'm quite sure that many people still believed the world was flat hundreds of years ago. And yet, they persist. This is explained by a force that is opposing the spread of knowledge in this particular area, a force composed of people that are placed in my final category...
3. People that are willfully ignorant, irrational, and / or malicious. Some people have simply made up their minds, and no amount of evidence and reason could ever sway them otherwise. And there are others, about whom I have written written before, who deny the theory of evolution in order to create a false controversy and generate a false enemy. It boils down to power and influence.
I would also like to point out that I am absolutist about virtually nothing, save evolution. There are incredibly smart people who believe in god and can use logical argument to support their position...likewise, there are atheists who can do the opposite. Reasonable people can disagree about abortion rights, and there are powerful arguments on both sides. Reasonable people can disagree about global warming and what we should do about it.
Alternatively, there are no reasonable people that are actively arguing against evolution. Not once in my entire life have I read a reasonable, logical, and honest argument against evolution by someone who actually understands evolution. The people that attempt to make them are either uninformed or deliberately disingenuous. Denying evolution is like denying the Holocaust, except that there exists far more evidence for evolution than there is for the Holocaust.