As for it being nonsense that some might load a single magazine with more than one kind of round, I will agree that to do this is nonsense, but if you think NOBODY does this, you're very wrong.
We had a guy in our grassroots state based political Pro2a forum get in a defensive shoot with his Glock 30, and this guy quite literally put two entirely different brands, weights and style of .45 ACP ammo in to a bad guy at a gas station.
I wouldn't do it either. Then again, I wouldn't tape labels to my magazines but whatever works for ya.
The shooter that flung Cor-Bon Pow'r Ball and 230 FMJ at his defensive shoot was not charged. And no, Mas Ayoob didn't speak to the local DA on his behalf. Not sure if that gives you your dose of hyperbole, but I gave it my best shot.