The reason one couple are treated differently from the other is because they operate differently.
H&M are the ones who set the pack on Catherine in the first place, the ones who tried to ruin her reputation and turned it into a free for all by Meghan fans. Without fail, those who make the worst comments about Catherine are always massive Meghan fans, who feel emboldened to say what they do about her because of what Megan and Harry have said about her They show no compassion towards her despite what she is suffering through. William and Catherine have never said a negative word about anyone, ever.
It is wildly different commenting on the appearance of M vs C for many reasons, not least of all Catherines ill health. However, Meghan on the other hand wants celebrity, she courts celebrity, she needs it, she wants that fame, comments about appearance are par for the course when you want to be a celebrity influencer, that comes with the territory she is claiming a piece of.
Of course people are going to comment on her appearance when she bounces onto a red carpet, playing to the cameras and acting all coquettish and fame desperate, promoting some clothes from a friends designer label or a friends make up line, and on top of that that everytime she stays out of the public eye for a while, she returns with obvious cosmetic facial tweaks that can't be distracted from by changing her hairstyle. Yeah, people are going to comment.
Back to Catherine and when is too old for long hair .........