Yes, I agree, I think there were definitely some articles where you can suspect class and cultural differences and just plain ill will and bullying and this is one of them. The problem here I think is that a makeup artist posting a photo of the oh so trendy avocado toasts while gushing about his newly royal host just does not sit well in a royal context. It's influencer fare and many people would go
even then. But I think this is where the issue of cultural difference and also class may come in. Let's say someone has been even slightly socially mobile, not necessarily in any negative sense, and sees things like avocado on toast as markers of their ascent, should then people with a different background, who have never had to make that journey shoot them down and make fun of them? I think her lashing out at Kate may come from this kind of a very hurt place, Kate knows what not to do and the list may seem endlessly long from the perspective of someone who does not. You would not want just anyone to tell you and a friendly sister in law may very well feel like the right person.
Just playing the devil's advocate...