The crux in all of this is for this is that some places have the gall to charge extra for nitrogen.
Luckily, the biggest player in the nitrogen tire game, Costco, doesn't charge extra for nitrogen. If every place followed this lead and also didn't have a line item charge for nitrogen; then all these comments would take on a completely different bent.
This would work, even if they buried that fee into the tires or a higher mounting fee or somewhere else.
The shop would be thought of like a "top tier" tire shop. Breaking the fee out is a bad move that makes them seem like scammers or nickel-dimers.
It is a bit like the conv vs synthetic arguments or even premium vs regular fuel that boils down to price. If both items were the same price, the consumer feels better because they got something "for free".
If anything this is a case study in marketing and human behavior
Analogy:
Cheeseburger $10
Hamburger $10
Customer response: "What a deal, you get cheese for free"
Cheeseburger $10
Hamburger $9
Customer response: "What a ripoff, $1 extra for cheese" (nobody will say or think I saved $1 by declining cheese)
(i stole this analogy from someone else who was commenting about United's new airline baggage fees)