I think that that specific joke could be, in the proper context, a satire of privileged people's perceptions. But when it's not a character on a comedy show or something like that, it could seem like she actually thinks that (obviously that's a thing no person of at least almost average intelligence would think, but, honestly, people on the internet have thought worse). I would suggest, in general, to give people the benefit of the doubt that a joke was meant as satire, or maybe that they were drunk.
I think that this stuff is stupid. People make mistakes! Even really bad mistakes! It doesn't make them bad people! Why do we need to hold publicly-viewable people like celebrities and apparently anyone with a Twitter account to such a high standard?
I would presume that part of it is the need to feel better than people? "Hey, look, that person is making more of an ass of themselves on the internet than I am!"
I guess that "online shaming" might have a place, but in general I think we should let people on the internet do what they want, get it out of their system, and if we don't like it, ignore them.