I'm shocked at Rojo's take on this. I think a few things can be true:
-Mu deserves credit for running fearlessly with the leaders. When they hit 1k and she still looked good, I was thinking to myself "could she actually win this?" It made the race more interesting. I also would have had no issue if she sat back in the pack and tried to see how many people she could catch on the way in but I liked seeing her go for it and try to win the race.
-Mu showed through 1400m that she has what it takes to be a more-than-capable miler. Even if she slowed way down, she would still have likely broken 4:30. That's outstanding for a 19-year-old and remarkable range for someone who runs 49-mid in the 400. Of course she didn't actually finish the race, which leads me to my next point...
-Barring an undisclosed injury, it is hard for me to view dropping out as anything other than a weak move. Unless she was genuinely injured (there is no indication this is the case, but she did not speak with media after the race so I can't say with 100% certainty), I'm not going to support an athlete at any level stepping off the track and giving up with 200m to go in a mile. Quitting just because you can't win isn't a great attitude.
-If Mu tweaked something or was genuinely injured, dropping out was 100% warranted and the correct move. No reason to risk further injury.
-Mu may be the Olympic champ, but she's still only 19 years old. She doesn't have a ton of experience racing as a professional, and she has ZERO experience running an event that is out of her comfort zone against some of the best in the world. She did not handle it well but she is hardly the only 19-year-old to react poorly to an adverse situation. She should not be endlessly criticized for this. Move on and learn from the experience.
-Hopefully this outcome will be a good thing in the long run. Mu didn't lose at all after NCAA indoors last year and since then had not just won every race she was in but dominated it. So to go from that to being in a race where you're struggling to hang on to sixth is a huge adjustment. Every athlete needs to learn how to lose eventually. Though I still don't think Mu will be doing a lot of losing this year.