One other important thing about passed balls/wild pitches is if the pitcher does not throw the pitch that is called and crosses up the catcher. Most times those will be scored against the catcher as a passed ball because they often hit the tip or part of the catcher's mitt. But really that one should be on the pitcher, and many people watching a HS game with no replay have no idea the catcher was crossed up and blame him.
I agree the catcher's fundamental job is to catch pitches. But the further up the youth chain you go, pop time becomes more and more important. With scoring runs at a premium, teams tend to really take advantage of catchers who cannot get the ball down to 2nd base quickly and accurately.