This logic is all well in good if people are actually pushing for that living wage. In reality though it seems like a lot of people who don't tip are just being cheap and are are taking advantage of the fact that part of these people's pay comes from tips and are using that to basically get cheaper labor.

People who refuse to tip out of "principle" but also refuse to do anything to change the existing situation are just as guilty of exploiting workers as the employees who rely on tips are.