He's a billionaire. The government defends his billions from being redistributed by angry dying people. He doesn't want potential revolutionaries to be able to communicate easily.
This is the right answer. HN likes to think of Bill Gates as a techophile because that’s where he started, but today he’s foremost a billionaire with more to lose than to gain.
And Warren's actual proposed rate, 3% for everything over $1 billion, is outpaced by the 11% annual rate of return for the S&P 500 over the last 30 years. A wealth tax would just slow down how fast the rich get richer.