"Let down by the team"
What kind of cop out excuse is that?
It's his fucking job to motivate the team isn't it? That's one of the lamest excuses that gets thrown about in football. What the fuck is he being paid for?
Postecoglou has his flaws but motivating the players isn't one of thems. Its largely due his motivational ability the team isn't sitting mid-table. I really can't think of a coach better at motivating his players.
I believe he knows the players deserve a bollocking after that. The hard part is because he isn't a big name manager, he lacks the authority to let loose on them they way he might want. He will get his message across in other ways. But make no mistake the players will know that's not acceptable.