This only makes news because it involves an Arab-American at an airport, but really it's not a particularly unusual thing for monolingual Americans to protest against writing in other languages. Look at all the attempts by various city councils to force store-owners to make their signs half English.

The protests seem to be most severe when the written language uses an unfamiliar script. A sort of visceral panic seems to set in. But really, what difference does could it possibly have made what the shirt said? The people who complained, of course, are simply frighted fools, and I suppose they are unavoidable these days, given the political climate. But for security officials insist that this gentleman remove his shirt--that is simply outrageous. Are they just as stupid, or do they simply pandering to the paradoid whims of any xenophobic nutjob? Pray tell, how does changing a shirt mitigate any supposed security threat?