Interesting. I doubt my next statement, but I have to wonder if this is a setup that was carried over from when before gas stations were self-service (I was actually shocked how you used to not be allowed to refuel your own vehicle). Maybe something along the lines of “This setup is cheaper to run and if it’s only the underpaid employees complaining about a less-than-ideal way to fill up tires, that’s a cost I’m willing to eat.”