He wasn't necessarily disparaging Guadalajara, after all he went to med school in Nigeria. It is just that someone who had such a lofty position might have been expected to have come from a more respected American medical school. Usually Americans who go to foreign (particularly Caribbean)medical schools do so because they cannot gain admission to American ones because they lack something (grades usually.)
HEY-I went to Tampico, Mexico (it Sucked.) But Hundreds of US students did so and some of us turned out Very Well. They "Milk the Act" with those premed courses and MCATs (but I did OK on the Latter)