So...if the age of the canyon is explicitly stated on their website, how is it that they're "not permitted to give an official estimate"? How is a statement like that, which obviously is coming from the agency, not an "official estimate"?

Yes, the fact that the book is being sold is pretty stupid. I'm not even going to try to dispute that. What I'm saying is that the title of the thread and some of the statements PEER is making are misleading and inflammatory. What's actually happening is that staff aren't being trained to distinguish creationism from science, and that they've for some reason decided to sell a creationist book.

While I'm confused that they'd refer inquiries to headquarters regarding the age of the canyon (instead of pointing them to the visitor FAQ), I don't see how that somehow equates to the park service (as an entity) refusing to make such a statement, since the information is right there for anyone who looks for it. PEER has some real concerns, and it's unfortunate that they have to mislead people to draw attention to them.