Dear Jackie: I think the clue to what is 'bunk" is whether or not it deserves scorn. The people thousands of years ago formed opinions based on their ability to learn and understand the world around them. Their ideas were sadly erroneous, but need not be called bunk. When lazy or misguided people today choose to ignore the teachings of the brightest people, their errors need not be condoned, and may rightly be called "bunk".
The creationists are simply misguided, and their views do not deserve much respect. When they try to lower educational standards, it is justifiable to call their beliefs "bunk".
Anybody who has seen Grand Canyon, or good pictures of it, and can still profess to believe it is only a few thousand years old deserves no respect whatsoever.