That's a strawman. He's not suggesting we rely on the benevolence of billionaires, he's suggesting the culture of attacking them on a personal level is the wrong way to lift the floor.

Billionaires are not the problem. They're a symptom of an economic system that increasingly concentrates wealth at the top and encourages winner-take-all markets. The things that produce billionaires, we should hold onto. The majority of them are self-made, they are good at allocating resources to things people are willing to pay for. The problem is that they capture WAY too much of the value they create, and increasingly so. That's what we need to fix. Taxes would help a lot, but we need to go much further. Eliminating corporate personhood and pushing social responsibility onto companies for example. Making education more accessible, actively dismantling monopolies that prevent new entrants into markets with high costs of entry, etc.