You "concede" that (a) is false? That's quite a strong claim. At least with "the government" managing it, there's at least some degree of democratic control, accountability, scrutiny, and influence. When that management is left to private enterprise, that's not the case.
Then you're getting into a philosophical debate about how morally "right" democracy actually is. That's dangerous territory.
I'm not saying I have a better idea, I don't, but democracy has been the driving force behind some pretty heinous stuff over the centuries (most obviously the resistance to equality of race, gay rights and universal suffrage). It's just less terrible than the alternatives that exist in the world today (e.g. dictatorship).
At least in giving your money to a Buffett, a Gates or a Feeney you have some evidence that they intend to put it to good use.
