(that very amusing S Club Jo clip aside) I don't know why everyone has to debate the hypocrisy. The jokes were all made in good jest. Nothing to do with cancer, the jokes were around the "WHERE HAS SHE GONE" hysteria and the way the media and social media went OTT about it. It really was quite ridiculous and it gave us all a chance to be very British and take the piss out of an absurd situation. It's fine.
I don't think she's done anything wrong, either. She has cancer, she took some time to wrap her head around it, she started chemo. Whether she should or shouldn't have said anything really doesn't matter because it's okay if she made a mistake or got the PR wrong - she has cancer. It's all bit grim for twitter to start accusing her of some pre-meditated strategy to keep secrets. Blaming the State or the Palace is a bit unfair also, they were probably just bowing to her wishes. Whether you believe she deserves her space or whether you believe she is owned by the public really doesn't matter either - the argument about her judgement (or lack of it) plays a distant second to her diagnosis.
The prognosis seems good. It'll all be fine and we can still joke about how the Palace fucks up from time to time. But she hasn't actually done anything wrong.