Just remember we all split hairs around here. It's like saying "Only hand wash your MF cloths and air dry them" over those, like me, who prefer to stick them in the washing machine and dry them in the dryer. IMO, the use of Dawn to strip the wax came about because of Sal Zaino's suggestion prior to applying the Z system. I have never read any hard facts that Dawn provides more stripping power over other detergents to justify using it over what you have stored under your kitchen sink. All dish washing detergents strip wax, otherwise they wouldn't cut the grease from your pots and pans and if they don't do that, people won't buy it and it'll soon disappear from the shelves.
This topic has been brought up before and there are plenty of people here that will swear by Dawn. There's just as many people who don't say anything and use something else and the end results are the same.