David's actual experience with demons was severely limited. He'd only seen them once or twice - that he was aware of - because Uncle James seemed to know them. Invited them into the house, talked to them in the living room or in the kitchen. Usually there was lots of money involved but sometimes they just... said a few things and left.
It was a bit unnerving to know that anyone could be a demon. It would do him no good to think about it constantly or be hypervigilant about it - he'd wear himself out in a matter of minutes.
People were arguably different though. There was no such thing as a good demon or a bad demon - they were just demons. The fact that there were good people and bad people really said a lot about people in general.
"Cal if I grow up and become a bad person... do you think we could still..."