This is a flawed story
This is a flawed story looking to capitalize on over generalized stereotypes. The "clipboard" guys are the Service Advisor who only reports to you what the Technician (also commonly but incorrectly referred to as the mechanic) finds and reports on when doing the actual work.
Service Advisors write you up, handle customer interactions and sell jobs. Outside of airing up tires from time to time or plugging in a quick scanner, they don't work on cars one bit. At least at any franchise dealership.
A new crew of Service Advisors is possible, but not the unknown factor here is the Technician who may or may not have intentionally assessed the pads being too worn. This is the most probable thing, assuming that you did a proper inspection of your pads with HF tools than he was able to do while the vehicle was on a lift.
Second to lastly, it's generally good practice to replace the rotor, or at the minimum resurface them, when replacing pads. You mentioned the rotors appeared to be WORN but within specs (not sure how you measured that... I didn't see any mention of a micrometer) but a resurface could remove a good amount of material, so your own assessment of them being worn may indicate the tech didn't think there was enough material to still be in spec after resurfacing. Or it could be the tech's default move to go straight to suggesting full rotor replacement. That would also save the labor of the resurfacing since that takes a good amount of time to do, makes the rotor more prone to future warping, etc. Too little data here to make a full analysis on that.
Lastly, something you're probably not aware of, but shops are legally required to give you the old parts after a repair. So assuming they do this (most do...), you would have had a perfect opportunity to inspect those 2 or 4mm pads in your hands, while not stuck inside calipers, upsidedown under your car using a flashlight and HF tools to which you would have been fully able to hold the shop accountable to their repair.
Next time this happens while you're at the dealership, ask your questions, ask to see the brakes while it's on the lift or see a picture if their insurance doesn't allow customers to stand under a car while it's up in the air. Like you said... It's not rocket science.