First, you need to know the context of the remarks. Obama was visiting Mexico. Mexico complains about U.S. guns, not because it is a sizable crime problem; but because it is a lever to ask for more money out of the U.S. government.
Bingo! The situation between the U.S. and Mexico is thus: Mexico wants their illegals to send billions of $$$ back to her; drugs go north and more billions of $$$ come back to Mexico. Where things got bad was that as long as corruption along the border and among the government officials was kept "within reason" everything was okay. But, the Mexican feds allowed things to get too out of hand, and the cartels really started pushing them around. I think its gotten to the point were Calderon needs American intervention but, for Mexican national pride and internal political reasons, hoped that by blaming the U.S. for Mexico's problems, and Obama being Obama, he'd get U.S. resources w/o getting U.S. troops either on the border or inside Mexico. Calderon is really desperate for U.S. help. He got way in over his head when he declared war on the cartels, not realizing how much they had really taken over Mexico. The DoD JFC paper on Mexico rapidly becoming a failed state was spot on.