He calls himself a liberal. Liberalism needs Democracy. Democracy needs corporate backing (Democracy works by corporations funding think-tanks, the think-tanks come up with the policies, they arrive at consensus, which is the collective interests of the corporate backers, which lawyers will then turn into a bill, lobbyists take it to Washington and get Congress to sign off on the policy, and then the MSM sells the policy to the public.) The Bill and Melinda Gates Foundation is one of the biggest corporate funders of Think-tanks. Therefore, to be a liberal in the US in modern times = to be a supporter of Gates, and it does logically make sense for him as a liberal to support Gates.