She can afford to live in a castle, and she wants to live in a castle. There's no need to say she has to feel guilty because other people can't live in a castle. Unless you're the unluckiest person alive, there's always going to be people who aren't as fortunate than you. In her case it's easy to point a finger because it's a castle, but honestly where's the cutoff? Should she feel guilty if she had instead chosen to live in a less expensive but still large and nice house? What about if she lived in a modest one? She still has a house and those other people still don't. Should she feel guilty because she can afford fine dining while many people can't afford to eat? What if she chose to eat only fast food? There's still other people that can't afford to eat regardless of the quality of food she chooses.

I'm not going to pretend I know anything about how she uses her money outside of what's presented in this meme. She absolutely has the kind of wealth where it would be morally responsible of her to use some of it to help others less fortunate. Maybe she does that already, maybe not. I don't know.

If she doesn't then yeah, maybe there would be a reason for her to feel guilty; but even then I wouldn't say she for sure should. But for the sake of argument let's say she does regularly contribute to charities. Should she still feel guilty about living in a castle? She's already contributing, but she could contribute more if she didn't live in a castle. But that begs the question, how much should she have to contribute? If she still has enough money left over to live in luxury should she feel guilty? I'd argue not.