Actually, your razor is made out of stainless steel, not stain proof steel. Try leaving a stainless firearm in a humid environment without proper oiling and see what happens. Take some Flitz metal polish on the end of a Q-tip and polish the stains off. The residual polish will protect your razor from a repeat of the same issue. If you're going to store your razors for a couple of weeks or more, just take a cotton ball and wipe it down with mineral oil. It rinses off easily under running hot water the next time you want to use it. I understand your disappointment after paying that kind of money for a product. Stainless steel will require some preventive maintenance just as will high carbon or tool steel. Not as much, but not totally maintenance free either.
I use petroleum jelly on my stainless firearms. It comes off pretty easily and stays where you put it. It works well on blued steel too. I imagine it would work well on a stainless razor. And you're right of course. Stainless is not equal to rustless.