>>150012014The team that is fielding doesn't want the batting team to get any runners on base. 4 balls and the runner advances to first automatically, 3 strikes and he's out. Calling a strike right down the middle as a ball is egregiously bad and helps the batting team at the expense of the fielding team, which is why the pitcher and catcher were irritated.
The count was 1-0 (1 ball, no strikes) before the pitch and should have gone to 1-1 after a strike, but it became 2-0, which is a harder count to work for the pitcher and a little more advantageous for the batter.
Btw if the ball is outside the strike zone and the batter swings at it and misses, it should be a called strike too