While I agree it shouldn't go on in what is supposed to be a civilised sport, the point is it does and it works. You only have to look at how the Man City players surrounding the ref pressured him into overturning the penalty decision he gave in our favour up there a few months ago. No way he would have done that if they had all stood around politely and just accepted his original decision.
Until such time as the FA/PL clamp down on it and direct refs to start giving cards to players who do it, we should absolutely keep doing it if it gives us an advantage.