Plus to be fair to umps (something very few of us want to do during the game), technology is at the point where each pitch can be scrutinized with great detail. There are multiple angles showing the strike zone, the pitch (showing its movement) and how it may catch a corner of the zone before it drops out of the zone and into the catcher's mitt...and these people are supposed to be able to discern this (in a microsecond) with accuracy. These umpire report cards were never available before either. Technology has advanced to the point where their performance receives instant feedback and we can see just how "bad" humans are at calling balls and strikes consistently, with accuracy.