Once again, our Canadian friends seem to not understand the American system of government. Not all states have a death penalty though the federal government itself does. The prisoner in question was not facing a federal sentence, but that of a state. The federal government is free to make treaties with other nations while states may not. The federal government cannot, however, dictate what a state may or may not do under its laws unless it legislates that law for all states.
That means that while the federal government may be willing to abide by Canada's terms, the state in which the prisoner was to face the death penalty, was not. The catch is working out an agreement that the state government itself would be willing to abide by.
So please do not lump all Americans into a basket of death mongerers because we are not. Fourteen states, the District of Columbia, and all US territories have abolished the death penalty.
As to the KFC remark, well, Quebec's contribution to world cuisine, the mess of cholesterol known as
poutine isn't exactly any better.