I think the Dawn dishwashing liquid step got started by Zaino. There web site states "It has a high alkaline content which cuts right thru carnauba wax, paraffin, silicone oils, etc. This will get your paint finish squeeky clean and wax free."

The idea of using Dawn dishwashing liquid to strip away old waxes and polishes may or may not be a fact. Some detergents are formulated to break apart oils other are formulated to add oils. Skin care products and medical preparations can attack oils quickly and aggressively.

As far as detailing, I am not certain of dishwashing liquids effect, though I have used it under the guise that I was stripping off old waxes.

The cool thing about detailing cars is that there are so many different manufacturers and products and ways to apply, that you can mix and match until you find a system that gives you the effect you desire.