I can't speak to other science denialism, but I spent some time in an Orthodox temple where the rabbi was a strong opponent of Evolution. (I spent time there when I disagreed with the rabbi so much only because my parents belonged there and so I didn't need to pay any dues to join.) The rabbi's argument basically boiled down to "Scientists keep changing their theories. Our 'God did it' theory never changes. Therefore, our theory is stronger and theirs is weaker, ours is right and theirs is wrong."
Religion has a strong reliance on the past and a strong element of momentum. You do X because Very Religious Person Y said you should and therefore your father, his father, and his father did X. X has been done for generations and any changing of X would be against your religion. If a new situation crops up, it must be somehow fit into the most applicable existing situation and made to follow the Old Rules. Any change is bad because it means veering from The Way Things Always Were. Even if they actually weren't always like that, the past will often be retconned to either ignore unsavory events or to re-write what people did. (e.g. The bible says Abraham served milk and meat together. That's not allowed in the Jewish religion but this was before the Kosher laws were given. Still, having that big of a figure ignoring Kosher is icky so that passage is "retconned" by an explanation that he served them in the proper order and separated in time just the right way,
The end result of this is that science, with it's ever-changing theories, is seen as bad - even though the theories change to better suit the data. Meanwhile, religion, with it's never changing rules (or, at least, rules that "have always been" this way once you retcon them) is seen as better.