"Adults know all sorts of things they're not supposed to know. They just pretend they don't know so you don't look stupid when you tell them." The way they talked was much like everyone was dancing around the drooling dog waving their sandwiches in the air pretending that the dog didn't exist. David wasn't an honest boy but he could see the dog everyone was trying to ignore and he wasn't very good at playing the invisible dog game.
Even now when Mr. Schubert looked at him, he squirmed a little in his seat, keeping his gaze glued to the sandwich.
"Uncle James is... not good people." Awkward, clumsy, tripping over the imaginary-not-imaginary dog. David didn't want to say that he was 'bad people' and 'not good' didn't necessarily mean 'bad' but it sounded like 'bad' covered up with a holey blanket.