Mancini stormed on to the pitch after City’s 2-2 Champions League draw with Ajax on Tuesday at the Etihad and confronted the ref.
He had just seen his side have a perfectly good goal and penalty claim turned down.
Mancini then challenged a cameraman for following him off the pitch.
Platt said: “Why wouldn’t the manager be frustrated? Why wouldn’t we all be frustrated? Players are frustrated, supporters are frustrated and so are the staff.
“Robbie has gone on to the pitch and spoken to the ref. As he comes back, he turns around and has a camera in his face for 30 yards.
“He turns around and says that it is enough.”