That was my first thought. They've been complaining like crazy that our subsidized corn has been selling for less than it costs them to grow it. They've been saying we're putting their farmers out of business, and have been particularly upset because corn is such a vital part of their culture. Now when corn prices go up, they're complaining about that.
"Corn prices in Mexico have climbed sharply over the past year following widespread speculation in markets for both locally produced and imported grains, due to uncertainty about how much U.S. corn would be available for Mexican importers."
Speculation, that's the operative word here.
You would complain too! Now their farm are destroyed and they became dependent on US agribusiness (the later employing their displaced farmers as "undocumented" laborers) and their food costs more. Typical bait and switch tactics.