There were 732,473 pitches thrown across baseball during the 2019 regular season. The Pirates' pitchers threw 24,862 of them. The Pirates' batters faced 23,525 of them. With a sample size that large, some miscues are inevitable. To err is human and whatnot.
While player mistakes are a part of the game, umpire mistakes are usually more frustrating. Sure, there are other factors like framing and sequencing that can influence a call, but umpires usually take the heat. However, sometimes the blame is justified, and when you open an article looking at "the worst ball and strike calls of the year," you are probably safe to assume they are the guilty party for these blunders.
To determine what the worst balls are, I measured the pitch by how close it was to the middle of the strike zone. For the worst called strikes, it was which pitch was the farthest from any part of the zone.