Look up the definition of a theory. It is not an "idea" or a "guess" when the term is used in science. A theory is the highest form of documentation -- as there is no way within science to "prove" something.
Calling the idea that the Grand Canyon is 4,350 years old and was created by Noah's flood a "theory" is absolutely incorrect, and is designed to falsely equate that "idea" or religious belief with a scientific theory. Sort of like the old, "they're both theories" nonsense when comparing the theory of evolution and ID.
Also like the attempted redefinition of "science" so as to include various religious beliefs. Didn't Behe have to testify in the Dover case that his definition of "science" was broad enough to include astrology? And this is all done to try to sneak religious ideas into science, and hence into the science classes.
Sorry, but this is one of my pet peeves: co-opting the terms of science in an effort to gain false respectability for non-scientific ideas or religious beliefs. In many cases lately this is done to fool school boards.
See my FR homepage for some good definitions of these terms.