The article omits an important fact:

The public's gold was exchanged at $20.67 per troy ounce, but months later, the official price of gold was raised to $35.00 per troy ounce. Essentially, the public were not properly compensated for turning in their gold.

"In 1934, the government price of gold was increased to $35 per ounce, effectively increasing the gold on the Federal Reserve's balance sheets by 69 percent. This increase in assets allowed the Federal Reserve to further inflate the money supply."[1]

[1] http://www.history.com/this-day-in-history/fdr-takes-united-...

EDIT: The article also fails to mention that "violation of the order was punishable by fine up to $10,000 or up to ten years in prison, or both." http://en.wikipedia.org/wiki/Executive_Order_6102