It is a crap tactic, but its safer than a tackle, trip, elbow or a two handed push from behind which most often aren't given red cards either. I actually prefer a super quick wrist tug (pull down) than a jersey pull, its a lot more discreet and less likely to be called.I still say a jersey pull from behind is a crap tactic and disrupts the flow of the game. It is used by defenders that just got owned, they had their chance and miffed it. Many times the jersey tug comes after the defender committed other fouls that the offensive player managed to stay on their feet through and break away. In my opinion the current implementation of the laws is too easy on defenders in general and this is just a glaring example. There is a reason that offensive players learn to flop as a way of protecting themselves.