look at the best managers, Fergie, Wenger, Mourinhio etc when do they ever hang their players out to dry? They'll make up some shit about the ref to get the media from talking about how poor their side was on a day or how bad a player was and onto them and the nonsense they're spewing. You really have to do something beyond stupid to get a bad word out of them in public (in private different matter but thats to be expected)
I have absolutely no problem with a manager saying 'we were terrible' today. Bobby did it. Singling out players though? Nah.
obviously but even then the top managers are reluctant ever to say in public they played bad thats how protective of their players in public they are. Fergie was the master of it.