The only similarity is that a person was with the team, and then they weren't. They both have about as much common with Julius Turner leaving the game yesterday, or Omoruyi leaving the Ohio State game a couple years back.
Biles stepped away from competition because she felt she wasn't able to safely compete. There was no altercation with a teammate or coach, there was no tearing off of her uniform or being escorted out of the competition space by staff, there was no throwing part of her uniform into the stands, there was no follow up comments blasting US Gymnastics. She instead supported the rest of her team and cheered on the person who stepped in to fill her slot.
Pope quit after he was pulled off the field of play because the defensive package was switched, and he got angry at the loss of playing time. He had an altercation with coaches, he threw his gloves into the stands, he took off his uniform while on the sideline, and he was escorted to the locker room. His departure didn't even rob his team of a player on the field, since he wasn't even supposed to be playing that down - and he was a situational use player to begin with. He then followed it up with a tweet bashing the program. He quit on his team because he was frustrated at not being able to play.
This is a different situation at pretty much every point.
- Biles was being asked to play, and she chose not to.... while Pope was being asked not to play, and he threw a fit over it.
- Biles actually stopped competing and allowed her backup to step in.... while Pope wasn't even competing in the first place, and was angry that his backup was getting a snap instead of him
- Biles continued to support her team from the sidelines.... while Pope had to be removed to the locker room
- Biles didn't cause a scene by arguing with coaches and throwing part of her equipment into the stands.... while Pope did
- Biles continued to be vocally supportive of her program.... while Pope bashed them on social media.
But sure, they both were with the team, and then they weren't. They are also both athletes, and both human beings. The similarities pretty much stop there, though.