I think you're being too sensitive. You made a joke of the situation (which is fine - esp since they took it as a joke) and they responded by joking around with you. The shirt is pretty low-brow, so why wouldn't their response be on the same level?
There's a difference between joking about the situation and joking about the person. I've worn this shirt many times and have laughed about it with pax, crew, and screeners. The one guy sounded dead pan serious like he wasn't joking. One would have to know me pretty well before even attempting that joke. I took a lot less offense at the second person based on the tone of voice than the first person. If he was joking, he sure didn't make it known.
Joke about the shirt all you want. I don't care. Just don't make it personal.