The US's role in suppressing food security around the world is well known. It doesn't matter how much they donate to food programs, which BTW themselves have a destabilising effect on food prices ans contribute to the problem when you violate the food sovereignty of like half the world.

I haven't looked into this in detail either, but I am guessing that the food program being talked about buys much of its food from US corporations. It wouldn't surprise me, especially since the US is such a major food exporter.