His point isn't particularly controversial, air security has gone too far. But he was looking for trouble by wearing that shirt, in his words mocking the "over-reactions to terrorism by the general public". He comes off as an angry person who doesn't sympathize with the genuine (and obvious) fears people may have. Ultimately he weakens his own point by acting so ridiculous; he gave the TSA and Delta a reason to mess…
I'll give him the benefit of doubt and assume he was not trying to provoke anyone, even though he could have expected the paranoid reactions of some passengers (probably a small minority that needs professional help, let's be honest).