Exactly! This guy is being described as a 40 yr. old white man. If this is true, I bet you this is just some innocent guy that somehow got the "wrong" substance on the bottom of his shoe, and simply decided to not wait around and put up with the Soviet style harassment of airport security.
Make an example of the next person who flees, and others will think twice. We're talking about attempting to prevent someone from conducting mass murder, so you don't just walk away when you determine its inconvenient for you. Right now, the risk for fleeing is apparently low, so raise the stakes. Bullet in the back forced upon themselves when they decided to break the law and break security. And save the Ruby Ridge bullcrap, there is no analogy between the two.
Which probably means he was a 25-year-old Arab, but they won't say so for reasons of political correctness.