I do like it on occasion yes, and those workers deserve a living wage. They don't deserve the luxuries of life that a doctor has, however.
Id agree the "hardness" of a job is difficult to quantify. A job where you sit at a computer all day but talk to people and run large projects to build houses or factories or anything like that, will pay more than a fast food person. They both are working, but it's different. Could the fast food employee design an electrical system for a food facility ? No. Could the electrical engineer work fast food? Almost definitely yes.