Pep doesn't make decisions because you are scared of what your United mates might say. He makes decisions which build football dynasties. This isn't even a controversial decsions: all the top clubs do it. You have to recruit an expensive, experienced, probably international goalkeeper as your number 2. This probably means that he has to sacrifice the thing he love, his trade, on a week to week basis. So to sign him and motivate him you tell him that he is the domestic cup keeper, all the way to the final should we get there.
The bigger picture here is that every single player in Pep's squad has to feel he is treated fairly. They have to trust him and respect him. The minute he goes back on his word in this kind of situation he destroys that. They are all Bravo's mate.
Bravo will play and, even though it weakens us, it is the correct decision by a man who knows how to look after a squad of top footballers and has them bonded as a unit.