It really does seem like operator error/inexperience with the KPA. Just because Fortus supposedly "uses modeling technology every day" doesn't mean he has bothered to figure out how to get the KPA to do what he wants. Trying it out "in rehearsal once" kind of speaks for itself as far as the time spent with the profiler.
Also, I would imagine there is some significant pressure inside the band NOT to use any kind of modeler on stage with GnR. It's an image thing. I realize it's just a guess, but knowing all of the old-school mentalities in a band like this, I wouldn't be surprised.