Conversations here can quickly go south due to one mistype or just from the reader being in a bad mood so I tend to tip toe when suggesting a cause might not be the bikes fault. Since I haven't met these people or seen their bikes, one can only specualte. Or ass-u-me.
The other factor regarding accelerated brake wear is weight. Another touchy subject. A fully bagged out bike or riding two up will definately increase brake wear. I once had the pleasure of trying to explain to a customer why his 658 was sluggish and went through rear brakes so often. He used it like a scooter doing errands in town and never took it on the highway cause it was slow and unsteady. Ummm, the poor bike was severely overloaded just by him sitting on it. Ever seen a lowered 658 overloaded? Ever seen a Russion Bear on a bicycle? I could hear metal groaning noises in my head. The centre of gravity rolled about on every bump or lean. I suggested using the maximum tire pressure. He said that was "two up" pressure and he never carried a passenger. Oh boy.
All I can say for certain is that it's not a bike specific problem or design error. Maybe a bad batch of rotors..... My F8 and the gf's 658 have been all over and still run the original brakes. Little mud use, reasonably loaded and I suppose I use a lot of engine braking as well.
As my French buddy always says "sorry bout yer luck!"