Let's look at this from a different perspective, now that the only person defending depriving service workers of tips isn't participating any longer: Why do we, the rest of the folks, get so upset about "them"? There are a multitude of reasons, of course, but deep-down what are the really distressing aspects of this?
Is it just a matter of fairness to the service workers? How much of it is fairness to the rest of us, who are indeed conscientiously living-up to the expectations of service patrons? Or are there other issues? Outrage that someone considers themselves exempt from the normal standards of behavior in society? Concern that the transgressions of a few will undermine the status quo which we prefer?
I wonder, also, if the sheer number of different ways people can be upset about this make it the banner issue it is.