They wouldn't. But I'm not convinced professional players need to be told where things are going wrong.
I'm rubbish at football but when I'm playing if things are going against us I generally know why.
As IBK said, no one player responds the same. None of us are the same and we all require different methods of management so we can achieve the best in our work place. If football managers, who understand their players better than any fan who only has an exterior perception, knew it was a pointless exercise, they wouldn't be wasting their energy.