The explanation for why this call was blown is quite easy. Since a person can not watch two things at once, the call at first is made by the ump watching the foot of the runner and listening for the sound of the ball hitting the glove.
If the foot hits before the sound, the call is safe. If the sound is first, the call is out.
Alas this poor ump followed the general rule, but the sound came from the pitcher not the first baseman whose foot was on the bag catching the ball.
“first baseman whose foot was on the bag catching the ball”
Interestingly enough, in the replays during the game, the first basement’s foot was off the bag by 3 to 4 inches....
You're absolutely right and it took me two views of the video which captured the whole sequence to figure out what happened....a luxury the umpire didn't have.