[_delirium]

Second, people aren't "expected" to give anything, regardless of how much money they have.

That's actually something philosophers of ethics (not to mention theologians and regular people) disagree on considerably; there is a pretty big range of positions on charity as a choice and/or obligation that are widely held and defended. The "never an ethical obligation" view is one, but probably isn't the majority one, though it's more popular now than it was in previous eras. But an HN thread about Sergey Brin probably isn't a good place to settle that debate...