Defending Manchester United players is something I do every now and then but, one thing I will not find myself doing would be defending players like Rasmus Hojlund and Andrea Onana not to also forget players who aren't ready to fight for this badge and club. Andrea Onana could be leaving this season and if that happens, Emilaino Martinez is one they've had contacts with already and he's no new name in the Premier League Competition. Do your checks right, he's been linked with Manchester United over the past few days.
You are right because not every players that's worth defending, there are players that from season to several others ahead they are always incredible but maybe an accident happened to them on the field and they got injury that lasted for sometimes and when they came back to play they couldn't do as before, is of course a defending something because it was the injury that caused it but for those who plays four seasons and only get an attention ones is not supposed to be defending because they have become a liability, before I defend a player or keeper I will have to no how you have been, not only on the season but others so that it wouldn't be unnecessarily, Onana is someone I cannot do that for also but there could even be praising to him from other people because not all the people like saying the fact when there is one.