Ya see, this wasn't a joke, per se. It was social commentary with a tinge of humor. The difference is that usually the person who passes it along generally agrees with the premise of what is being said. And the premise of the piece was "Don't give airport security to the inept US government, and racial profiling is 'common sense'".

Kind of like how you tend to hear more foul-mouthed jokes from people who usually talk like that, or more racially-biased jokes from bigots. What comes out of the spigot is generally what is at the source of the well.