I read the article and I can say is that he's one of those very "rational" people who maintains his rationality by excluding contradictory facts and evidence from his thoughts. He doesn't understand economics and he's trying very hard to justify himself.
It's embarrassing, actually, the extent of his ignorance in proportion to his power. He's angry at "art history majors", lawyers, and everyone else who doesn't believe that the accumulation of wealth at the expense of all else.
He talks about innovations that create wealth, which are real, but credits all the wrong people with them. I don't know who invented the aluminum can upgrade he discusses but I will be the agent who financially backed that was either the can manufacturing company (which doesn't require intense private wealth concentration), or investors who didn't need to be fabulously and exceedingly rich.
He takes issue with Warren Buffet for donating to charity and says "that money belonged to the middle class." But we know the middle class has been slipping under these policies he favors, and we know, despite his 5-1 claim, that his kind of "investment" is more of a 1-5 return (gives back one dollar to the rest of the economy for every 5 dollars the rich acquire to invest). So for starters, that kind of money doesn't go to the middle class. Second, he made clear that the rich should have more of it, so he was making a rhetorical point to shore up support.
Third, who the hell is he to say that millions of middle class Americans are more deserving of economic support than billions of world's poorest? Or that the middle class is more deserving of *best case scenario* minor improvements into consumer goods more than the middle class is deserving of innovations in public education or whatever various projects the Gates Foundation is supporting.