No surprise that a majority of people would be glad to see the plutocrats pay up some of their wretched excess.
That said, I think there are a lot of people out there who resent liberal billionaires supporting higher tax rates (largely higher income tax rates) that would affect all those trying to climb up the ladder a few rungs, but would have negligible effects on these uber wealthy liberals. People like Buffet don't have to show any income in any specific year, so income tax rate hikes are not a concern to them. The threat of a ‘wealth tax’ on their assets makes them vulnerable, for essentially the first time, to the liberal tax policies they have been supporting.
I still don't support a wealth tax, and think it's an unconstitutional slippery slope that will destroy our economy, tank the markets, markedly drop the value of people's 401Ks, and ultimately hurt the middle class the most. I was just conjecturing why there may be some reflexive support for it.