Now, there may be some validity to that observation, but as Keith Koffler has pointed out, if it's considered bad form for politicians to criticize the President when he's abroad, shouldn't America's schoolchildren likewise be immune from criticism by politicians on foreign shores?
Obviously, politicians being politicians, there's always been reason to remind them that criticism of the President should be subject to some time, place and manner restrictions. Perhaps President Obama is the first US leader who needs to be reminded that his criticism of his own country (and countrymen) should be similarly restrained.
We all knew President Obama wasn't a believer in American exceptionalism, but this is ridiculous.