This would have been better in the “Ask The Ump” section, but as an NCAA umpire, I’ll chime in, though I’m far from an expert.
Lots to unpack here:
First, theoretically, for the call to be overturned, the HPU has to basically be 100% sure he came off the bag. I had an NCAA game Tuesday night we had a bad throw to swipe tag. U1 called runner who was sliding into first to avoid tag out, came to me for help. As the HPU, I got a read on the throw, took a read step, and even got lower to watch tag/no tag, and I told him “it looked like he missed the tag, his tag never changed direction, never had hesitation (momentum slows when contact is applied usually), and never saw the glove bend due to pressure or contact him.” I then said, “but I also never saw space/air between glove and body, therefore I can not be 100% certain he missed the tag”. So the call stood. To overturn means the call almost surely was correct at first in the end.
Now, if you watch the Indians you should know the next rule. When an umpires INCORRECT call puts one team at a disadvantage, they have the authority to correct the disadvantage (and should do so).
Without video showing where the runner was, calling the runner out at first would indeed prevent the defense from making a play on R2 (now R3). Had they said “safe” immediately, they might have looked to that runner to make a play (or they might have stared at the ump like the 1B in the move “major league” on the final play!!)
My point is, it’s possible on a game ending pivotal play, both umps were so focused on play at first they might not be aware of where runner was...also unlikely he was almost 180 feet run in the time it takes to throw to first.
The other day, a KC Royal was tagged out bc he was confused by an umpires call that was wrong, and it got corrected to give him 3rd base.
Assuming the runner was not more than halfway home and likely to score, putting him back on third is likely the correct call.
Surprised all the fans who know the rules better than the umps didn’t know that