I see your point(s). I should mention - you buy a new device, under warranty it has a flaw and the end result is you get a "used" device in its place. That is pretty much what is happening. I suppose starting with a used or refurb then makes far more sense if the warranty is really not about repair or replacing your purchased device but a simple swap. Imagine that for cars, cameras and more...you know that would cause quite an uproar.
You have to very specifically define used here. And we have to determine when a phone stops being your phone after a repair. What part of the phone makes it yours? Is it the case? The battery? The logic board? Is it still yours if I replace any of the three? Is it still yours if I replace all of it, but still call it a repair?
Refurb aren't completely from used parts, and the pieces that wear and tear are replaced with each one (case & battery). Is it still used because the logic board was in operation for a month or two?
This sort of determination is irrational, and that's fine, but not everyone makes that determination the same way. But as ActionableMango points out, your defective device you are giving them is used. Is getting a "used" device with the wearing parts replaced with new that bad? Why?
Mr Smith - sorry your 2000 dollar camera had a faulty lens flange. Here, let us give you this "good as new" used camera in its place. I suggest taking your Acura over to the dealer so they can swap it out for a "previously owned" car in its place.
If it was a warranty repair, I'd have no problem taking the refurb camera. It has attention given to it no "used" device gets.
Cars are different, but they have a lot of parts that wear down involved. If I don't mod my car, and the replacement could be confirmed to have equal or fewer miles on the wearing parts, sure. But it is nearly impossible to guarantee that with a car. They are also a lot cheaper to repair piecemeal for the manufacturer, just due to shipping costs alone of parts and supplies. Shipping whole cars for replacement is expensive.
With a heavily modified Mac Pro, I'd prefer repair too. Although the new Mac Pro is easier to simply swap out, as the modifications are more likely external now. I'd wager that they will still repair in the case of bad RAM or SSD, but replace in all others.