Just wanted to retract this bit. It's incorrect logic, because now I know that in case of an injury, they are expected to draw from the individuals before the alternates. (Which in itself is a bit weird, and degrades from those poor alternates ever having any hope of competing, but I digress.) So it should really either be based on:
1.) What person in the 4th team spot would have helped the team most, and/or
2.) overall what arrangement would mathematically win the U.S. the most medals(?)
Some here think Grace is the best choice for 4th. That's fine, when you have a logically-supported argument. If Tom as head of the selection committee (who really needs to have a logically-supported argument more than any other person on Earth) had bothered to make any sort of coherent argument, this would have been fine. But he didn't, and that's really what is the worst part of this:
"Between Grace and MyKayla, there were tenths of a point between them at championships, and this weekend over the two-day period Grace ended up in 4th and so that's how we decided. Even though the computer tells us MyKayla on the team would be a couple of tenths higher..." "we're so so fortunate that our athletes are so strong that I don't think it's going to come down to tenths of a point in Tokyo. We didn't feel like it was worth changing the integrity of the process simply for a couple of tenths." –Tom Forster
If this was actually his thought process, then he just doesn't belong as part of a selection committee. If "the integrity of the process" would somehow be violated by not choosing top 4 at trials, there needn't be a selection committee.