United were beaten 4-3 at Bayern Munich in their opening Champions League group game - a fourth defeat of the season.
Yorke told BBC Radio: "Fourteen goals [in their last five games] - that is a lot of goals to be conceding for a club like United.
"I feel for [new goalkeeper Andre Onana], when you're in his position you are always going to get scrutinised, you are always going to get called out for it.
"That [goalkeeping mistake] is probably only a small part of the problem. Ultimately you have got to look from top to bottom.
"I think it starts with the manager. The manager has got to take some of the blame here, as much as the players.
"You listen to his post-match interview, he is saying it has to do with determination. Well I am sorry, that has got to do with determination from the manager as well as the players.
"I think that sort of standard is set from the manager - yes, the players are the ones who are going out there to try to get you results, but ultimately that determination he is talking about has to be generated by the manager. That will to win has to resonate from the manager and come down to the players.
"There is not one single player that we should be pointing the finger at here - it has got to be a collective blame throughout the team."