Of course it's strange. I suppose they know some things, just nothing overly informative or helpful. You know how it goes, things are lost to history, facts become myths and legends. They know Davy Jones once existed, they know there is a fabled jewel that supposedly grants wishes -- that's why there are plenty of people in this world who want it, too.

Everyone seems to know exactly that much, though. So if this is a distraction, as you seem to think, it might be difficult finding out the truth of why we're here. And how to get back.