Isaac Hayden's terrible follow through on Dennis Praet after the players challenged for the ball led to a straight red card for the Newcastle midfielder.
Yes the player questioned the red card, but the tackle was there for all to see, and Hayden was fooling no-one.
Bruce added: "I've got no complaints, the red card was a poor challenge. Maybe back in my day you might get away with that but in today's game then I've got no argument.
"OK, we went a man down but we've still got 10 men on the pitch and leaking four goals is not good enough. It's just not acceptable. We really do need to look at ourselves in the mirror."