Because it could be bluff, to extract most from City. Thats why the club cant be 100%, thus the player needs to tell the board.
I mean how fucking hard is it to tell the board anyway even if its fairly obvious. At least then nothing will be unclear and business will be done smoothly instead of this weird mess. There is no downside to it. He would have also avoided his injury as well, he had all summer long to say "i want to leave" to the board and then again in January. This all started in May 2019.
Pep said that he never asked to leave for some reason
Leroy and his camp have handled this remarkably poorly, no question.