Bayern didn't think he was good enough to want to keep and their fans thought he was disappointing.
https://www.bavarianfootballworks.com/2020/7/20/21329423/bayern-munich-analysis-philippe-coutinho-postseason-breakdown-barcelona-liverpool-thomas-muller
Its stupid but the clubs could solve it by naming every player that has it. Or say something like 14 of our 25 man Premier League squad have tested positive.
Keita has been injured a lot, though. Plenty of our signings take a while to get used to how we want to play. I can't remember when Keita first got injured.
Agree with your wider point, though. It's a s*** league.
I think people in football are mostly very confident or arrogant. They need to be to be good at what they do but they probably think they can do things no one else has managed to before, like keep Chamberlain and Thiago fit enough to play a lot of games.