He is absolutely incorrect.
If the dealer put a wax or sealant on it before you took delivery, let it wear out before you wax it. Unless you are OCD about your vehicle and you only want your own wax on it, it doesn't make sense to do what he suggests.
I'm just not sure how a hand wax is going to do anything better for your vehicle than the wax/sealant the dealer put on.
Secondly, and most important, I can't fathom how you safely strip the dealer "polish" off of the vehicle without A) Washing it first B) stripping it with a wash. So technically, you can't strip the dealer "polish" off of the vehicle before your first wash.
And, just so you know, stripping the wax off of a car and having a hand wax done can be a simple as this:
You can do it yourself VERY easily with cheap supplies from Walmart/Carquest/etc.
If you decide to do it, let us know and will will offer you some step-by-step supply/process suggestions.