I think you're putting a lot of weight into greed in terms of money, and it's my belief based on watching famous rich people talk that many of them want money, power, and status. The things they say and the way they can bring other people down, those are some ways that they can demonstrate that power or status.

And that makes sense if you consider what meaning money has to the ultra rich. People who have more money than they could ever spend will probably try to get more, but that alone wouldn't be satisfying. So then they're going to look to other ways to feel like they're on top of the world. One way to create that feeling is to knock others down.