Probably because they couldn't mentally handle any truth besides their own. Some people are so wrapped up in their beliefs, that they can't see beyond the end of their nose.

I'm writing a research paper on exactly this topic;) The main reason is of course religion, and the fact that evolution is fundamentally corrosive to religion since it brings an end to teleology. There's no goal in evolution and no designer, humans are just one species out of millions that all have evolved on earth for the same amount of time. The massage of evolution contradicts every attempt to take the Bible, or the Qu'ran, literally. Children tend to believe what their parents tell them, and in certain parts in the world there are children who are systematically told that evolution is wrong, by their parents, their teachers and their pastors. There is a whole network of propaganda that denies evolution, it even goes so far that there is a 'creation museum' that shows pictures of humans riding on dinosaurs. After the message has been burnt in the brain by systematic indoctrination, it's very hard to change the mind. And it certainly doesn't help that even in public schools, the education is pretty bad and evolution is very poorly taught. Most people don't even get how it works and still think that life evolves as ladder leading to humans instead of a tree of life. Here's an example of extremely bad journalism on the subject: http://edition.cnn.com/2009/TECH/science/10/01/oldest.human.skeleton/index.html?eref=igoogle_cnn They make it look like it's a surprise that humans and chimps have a common ancestor.

It is illogical and so are they.

If we "evolved" from primates where did all of our strength go? And that is just one example, primates have so many characteristics that would be useful to us, where did they all go? It seems to me like if we did evolve it was only in our brain development.

Let's not forget that it is the THEORY OF EVOLUTION. Theory being the key word. DNA similarities do not make it the same species. Darwin had theories. Most Scientific people know that unless it can be proven and be reproduced several times, it remains as a "Theory." I'm a Christian and thought that Darwin made many great observations. But there is yet one sample, let alone several samples that support his observations that were not faked. If you take this theory seriously find the evidence. Every time someone tries to "prove" it with fake eveidence, it just discredits the program.