Thomas Aquinas, Natural Law, and Occupy Wall Street

This could well be a sign held by an Occupy Wall Street demonstrator: 

Those things which some possess in excess of reasonable needs are owed by natural law to the sustenance of the poor.

The Catholic theologian who stated this?  Thomas Aquinas, the "angelic doctor" who is often cited by the magisterium as the Catholic theologian of all time.  The citation is from Aquinas' Summa Theologiae II.II, 66, art. 7.

Funny, isn't it, though?  We hear a lot about natural law from the magisterium and its supporters, when it comes to matters sexual--and especially when it comes to establishing the primacy of heterosexuals and what they happen to do over homosexuals, and the human defectiveness of the latter. 

But we almost never hear--certainly not from Mr. Dolan, president of the U.S. Catholic bishops' conference, and his Republican chums both in and outside the American Catholic hierarchy--about natural law as a basis for critiquing greed.  And yet the angelic doctor who laid the classic foundation for Catholic theology teaches that, according to natural law, what I possess in excess of my reasonable need doesn't belong to me at all, but to those who have little or nothing to sustain themselves.