Piracy was certainly prevalent. However, it wasn't so much practiced by nobles.
In that nobles generally did not do the actual pirating, yes. However, nobles were certainly involved in piracy, sponsoring groups of pirates that would operate near their lands and give them a portion of their profits. I know this was true in Ireland, and wouldn't be surprised if similar situations existed elsewhere.
One could also think of the Vikings as pirates of a sort, if you stretch definitions a bit.
However, you are wrong about worshipping a king. LATE European kingdoms believed in "Divine Right," but Medieval monarchs did not rule by Divine Right. It's really late-Middle-Ages up to the Enlightenment that sees absolutist monarchs. Even theologically steeped, powerful monarchs like Charlemagne or Alfred the Great didn't have anything approaching Divine Right. And they CERTAINLY weren't worshipped.
In a similar vein, aren't things like 'separation of church and state' a post medieval idea? Seeing so many people supporting more modern ideas like this is one of the exotic things that annoys me. But I could be wrong.
