Well I think you're wrong and I'm just as qualified to say that as you are to say I'm wrong.
There's no discernable difference in the amount of info we have on both Charles and Catherine's illnesses.
The difference is that one is an attractive youngish woman with a young family and therefore attracts tons more nasty speculation. Because she's an easier and more interesting target.
No change in tone or additional medical detail would change that. Even if you keep away from the lunatic fringe and restrict yourself to considering only the unpleasant affair rumours.