Why is every side character so stupid

They not only disagree with the idea of supernatural beings, but adamantly state that they can’t be real, even when placed in extremely insane situations. I understand they don’t have the context we do, but for example in season 2 ep 21, these people with SUPERPOWERS, are ignoring the things Sam is telling them, even disagreeing with him saying demons exist, because ah yes, that must be so crazy when we were placed in a random town together out of nowhere. It just annoys me when some/most of these characters are this stupid