"A lot of commonsense has gone out of refereeing," Bruce said after Blues' third away victory of the season.
"Referees have to stick by the letter of the law and old-fashioned commonsense has gone out of the window.
"People pay an awful lot of money to come and see matches - but not enough of them are 11 versus 11. The game is about 11 versus 11.
"And it's very difficult because you've got to take the conditions into consideration. It baffles me because the conditions were treacherous.
"I won't put up with players trying to maim players. But I didn't see horrible challenges. They were mistimed or down to exuberance, nothing serious.
"For example, why was Geoff Horsefield booked? Does anybody know?
"Afterwards, it was easier to ask my players who wasn't booked. I can't hide my admiration for the way my players have gone about it. I've got an honest group of players trying their hardest. We might not be the prettiest but my God we give it a go."