Jeff Bezos recently attended a gala for the Baby 2 Baby charity founded in honor of Kobe Bryant's widow. According to an account in the Daily Beast, Bezos kept silent during the donation request, until another attendee donated $1 million, at which point Bezos threw in $500,000.

While the Daily Beast characterized that as a "substantial sum," his donation produced an audible groan, ostensibly because the amount seemed small next to the $1 million that had just been donated. But the real scandal isn't that Bezos failed to match the previous donation. It's that the amount Bezos pledged is miniscule compared to his net worth.

Here's the math: $500,000 represents 0.000001 percent of Bezos's net worth of $197.5 billion. The median household net worth of the U.S. population is $121,411. A donation from that median American household of 0.000001 percent of its net worth would be ... 30 cents.

How can Bezos be so shameless? Two reasons.

First, Bezos is shrewd enough to know that when most people see $500,000, they think it's a lot of money, because it's more than they'll likely see in their lifetime. So insofar as he cares about his public image, he's not likely to take much flak for being publicly so cheap.

Second, Bezos does contribute to other charities.A few days after the $500,000 gaffe and perhaps in reaction the criticism it received, Bezos donated $200 million to the Obama foundation that honors voting rights pioneer John Lewis. While that's not chump change, it represents only .1 percent of his net worth.

While Bezos has increased his charitable giving somewhat, he's famous for being stingy in this area. Unlike his ex-wife (who signed immediately after their divorce), he hasn't yet signed the "Giving Pledge" where billionaires promise to give away half their wealthy before their demise.

Why does Bezos (and his peers) seem half-hearted when giving to charity? It may be an of the well-studied phenomenon that as people get richer, they tend to get meaner and stingier. Certainly in Bezos's case the public giving of the equivalent of 30 cents at a charity event exhibits a certain cluelessness.

Bezos did not respond to requests for comment.

Takeaway

Hopefully some readers of this column will be hugely successful entrepreneurs at some point. If you truly want to have a positive impact on the world, it might be a good idea to put in place a plan for charitable giving now, and stick with it as your wealth increases.