And when you etch it especially if you laser mark the metal that is end of it being fully passivated unless you redo it afterwards with nitric or citric acid. If you are going to spend $$$ on a stainless steel razor it certainly is worthwhile process to have to have done to protect that investment afterwards if the manufacturer can't or won't certify it is passivated to some sort of standard like what is used for medical or pharmaceutical by the FDA. Unlike aluminum or brass stainless is actually less safe for this application because of the potential blood poisoning from rust even in a micro form. Passivating to medical standards is a very simple way to allay those concerns and potential legal problems once one person dies and some slick lawyer pursues that angle in a lawsuit.
Stainless steel is about as stainless as non alcoholic beer is non alcoholic.
Equating guns to razors is like equating apples to oranges same as firearms to medical equipment which shaving devices are more akin to.
"Blood poisoning from rust." That's an interesting concept; one that I hadn't heard practicing more than 45 years as a medical professional. Usually hematologic infections are caused by blood-borne pathogens, and I'm not aware of any toxicologic effects from iron oxide in normal quantities, ingested or absorbed. FDA, ANSI and NSF as advisory agencies have a role in certifying the chromium content in stainless steel for use in food-contact substances (FCS) - a minimum of 16% I believe - but the exclusive requirement for passivation of medical devices is because of the requirement that laser engraving on those devices remains visible and readable through multiple, rather harsh, sterilization procedures. And passivation is simply the surface corrosion process that protects the metal surface, which occurs without acid treatment or pickling, naturally. The commercial acid "passivation" process here described is to remove any potential left-over iron particles that might be a nidus for corrosion. I have never, for example purposely "passivated" any of my stainless steel cookware, and it seems to be holding up rather well to a combination of heat and a variety of foods. But as I said, anyone is free to do with his or her razor as they choose - it's a free country, last I heard, and if you routinely steam-sterilize your laser-engraved razor, by all means, passivate away. It's just simply not necessary for the applications discussed here.