Creationists attempt to discredit anything that contradicts their religious view of the Universe. They often do so dishonestly, spreading tall tales to discredit science in the eyes of the average person who doesn't have time to research the claims.
Here's an example I came across today:
A Rancher in Wyo buried a sheep 20 yrs ago and for a kick, dug it up and sent it in for carbon dating. ....It came back that it was several million years old!
That's quite some claim! Who would have guessed that carbon dating can give a result of a "several million years old," when the method is only known to work up to about 60,000 years ago at which point the carbon radiation becomes indistinguishable from background radiation.
Creationists are inherently dishonest through the spread of false stories or they do not bother to verify the claims that they have heard. This one story isn't an isolated incident. It is common to find a fundamentalist claiming that human tracks were found alongside dinosaur tracks at Paluxy River, or that Noah's Ark has been discovered.
In this particular incident, when the man was shown how silly his argument was and pressed for more information; he changed stories. He stated that he heard about it in the 60's (making it difficult to verify), and that he "mistated" the resulting age.
When you come across an ideological person hellbent on convincing others or themselves that they are right, their claims should be taken with a grain of salt. If they are not directly lying, they may have tricked themselves into believing something for the sake of their belief system. It's a shame and it shows why more emphasis should be placed on critical thinking skills in K-12 education.