That powerpoint presentation from HiFicritic is absolute garbage.
"For an informative read about the potential limitations of Class D amplifiers, I suggest checking out: [link to slide presentation from HiFicritic]."
In what alternate reality does that pile of garbage qualify as "informative reading". It is utter nonsense. What it amounts to is some misguided person trying to think up as many potential issues as he can, for PWM amplifiers, and asserting that they are all inherently unsolvable, when the obvious truth is the complete opposite. I disdain this kind of misinformation.