He is a betting man. He himself says he and colleagues bet against the economy in the financial crisis and made shit ton of money.
Stock market/trading is a kind of zero sum game. For him to gain, someone else has to lose.
However, real economy is not a zero sum game and I dont think he understands that. AFAIK never was an entrepreneur, or created a business.
He advocates for a wealth tax, ie a tax on unrealised gains.
For realised gains, we already do wealth tax and thats called capital gains tax.