People love saying things like 'The club have made a mistake...' or 'Klopp was wrong to...' and 'It's baffleing that...' and 'I struggle to see why...' and similar. It makes them feel clever and special. A moment of swag, and if it can't be proven otherwise then all the better.
In reality football management is always about choices and compromises and decisions that are often out of your hands and, above all else, luck.
It's rare to the point of irrelevence for a top manager assisted by top level coaches and analysts and scouting systems and sports scientists and so on to 'make a mistake' in the proper sense of the word, e.g things such as not realising they have a top player or, pertinent to this thread, 'getting rid of the wrong player' or playing a player when they shouldn't have (another favourite among fan swaggerers) and so on.
Every decision will be based on lots of thought and consultation and discussion among top proferssionals. And there'll always be reasons for choices made, often reasons that armchair managers aren't aware of.
Not everything can go the way we, as fans, would like. Sometimes tough decisions have to be made and often bad luck can make a good decision look like a bad one to those who only look at the superficial.