Even with issues like polio where he's supposedly doing good, he does lots of harm from my understanding. Probably not though malice, but being a know-it-all who uses their money to shape policy, the end result is still the same. Having a tech billionaire in charge of medical policy has caused many more people to suffer from polio as a result than would have without his meddling. And that's the problem with billionaire: even if they try to be good, they're no dieties and giving that much power to unaccountable individuals means they can accidentally cause lots of harm. And often the have perverse incentives (see Bill Gates and all he's done to hurt education in the US, for example).