[The infield fly rule gives umpires the discretion to call an automatic out on a popup with more than one runner on base, largely to prevent the team in the field from intentionally letting the ball drop so they can get an extra out, since the runners can't drift too far away from the bag for fear of getting doubled off after the catch
"It's all judged on what the fielder does," said the umpire, who was stationed down the left-field line as part of the expanded six-man crew that is used in the playoffs. "Once that fielder establishes himself and he has ordinary effort on the ball, that's when the call is made. So it wouldn't matter whether it was from third base or on the line out there. It's all based on what the fielder does. That's what I went on, and that's what I read."]
The above is from a FOX News article. I read the actual rule from the MLB rulebook and that was like reading instructions on programming a TV remote after drinking a twelve pack.
The fact remains that the fielders flubbed the play, unaware that infield fly had been called. Sorta like delivering a load an hour late only to find out after you arrived that the delivery time had been moved back an hour, thereby making it look like you had a plan all along.