As much as all the "logical" and "rational thinking" folks in the world want to ignore and dismiss emotions and politics in decisions and actions, the truly rational thinking and logical decisions and actions understand, accept, and take into account emotions and politics.
I disagree; what one person hoards isn't available for others to consume. Both wealth and consumption are worth examining.
Savings \neq investments. It's been said that one reason the U.S. economy hasn't picked up as much as we'd like in the past few years is that gun-shy banks and corporations were sitting cash instead of investing it.
In theory the optimal economic policy is one that balances (1) creating incentives for investment against (2) encouraging demand for the products of that investment. The latter isn't a given, by the way: The "if you build it, they will come" notion that demand will always exist --- and, therefore, supply-side incentives for investors are supposedly all that's needed --- rests on the "no problem, we'll just assume we have a can opener" assumption that Homo economicus normally behaves rationally, with a view to optimizing his or her economic position. Those assumptions have been widely and, it seems to me, justly criticized (as the author of the post seems to agree).
All this talk of US income and wealth inequality... First of all, global inequality is falling. This is indisputable! Secondarily, the pie should be measured in actual consumption, not in income or wealth. Look at what Mark Zuckerberg consumes, not what he earns!