Like others have said, the main reason I felt sorry for Mirai was because of her reaction after her skate and receiving her scores, how she was so disappointed and upset that she was unable to contain her emotions. (I hope she's feeling better about it now!) Plus, I was probably extra sympathetic because I was rooting for her to make the world team in the first place, I was happy that she had made improvements this year and did pretty well on the Grand Prix, and recently I'd watched how hard she worked and trained with her new coaches during that 20 min. mini-documentary.
After Mirai's long program, I knew it wasn't perfect and that she wouldn't be on the world team, but I guess I was expecting something more in the 3-5 range, so 7 seemed harsh to me. But after seeing many posters here say that they could see the many URs in real time, that they weren't borderline and therefore not ignorable, etc., I can accept that her placement was at least not outrageous and that it was probably correct. One explanation for her placement being low that seems strange to me, though, is that she was "lifeless," her interpretation was poor, things along those lines. This mostly just seems strange to me because I didn't think Ashley and the other top U.S. ladies skated with signicant more "life" or superior interpretation here. I don't think Ashley is the very best in the world when it comes to artistry/presentation/interpretation categories in the first place, but when she's at her best, the confidence, fire, and polish with which she performs her choreography is what makes her stand out compared to many skaters. She was not at her best at Nationals, the same fire and confidence was not there, she was more slow, cautious, and visibly nervous (therefore making the audience nervous for her, taking us out of the program), and the falls marred her program -- same with Agnes's. Gracie's long program had more of an impact because it was clean and an amazing technical display and accomplishment, but she did not seem invested in selling the choreography or show much expression until after she completed the jumps, and the choreography itself is forgettable and juniorish. But all three were still rewarded despite not being as clean or artistically satisfying and inspiring as the earlier skaters (Cesario was probably my favorite performance-wise), so I guess I expected similar treatment for Mirai, being the highest ranked U.S. lady in Vancouver, being a former National champion, having a pretty good season with visible improvement, and having her own great skating and presentation qualities such as in her spirals (though not held very long) and spins (normally I'm tired of the ever-present layback > haircutter/side layback > Biellmann, but I love the one at the end of her long program! It was also the only spin that my dad who doesn't watch skating specifically pointed out that he liked). I'm not saying she deserved to be placed ahead of Ashley or Gracie anything like that, just explaining why my first impression after seeing her placement at 7th was that she was given harsher treatment than the other top U.S. ladies. And if picking what the USFSA perceives to be the right skaters for the world team is at all on judges' minds when scoring programs at Nationals, I wish the system for choosing the world team could be changed and based on factors other than Nationals like other countries.