It's not the money. It's the appalling spectacle of a grandfather telling a granddaughter he never had any feelings for her.
But you'd have to understand how galling the idea of talking about the family money is to most people in Buffet's class to see what might have provoked his reaction. And talking about it to anyone is bad enough, but going on Oprah...
Not that it at all justifies such an extreme reaction, though.