Listen, lady...

Ms. Heesley, the airline is a business, which is privately owned, and has the right not to serve you. They were obviously concerned that the obscenity on your T-shirt would offend other passengers.
If you wanna be an idiot, and you're egocentric enough that you have to broadcast your politics to everyone that sees you, you should at the very least do so in a way that's not offensive. If you can't handle that, it's gonna tick people off, and when you live in a society, that causes problems.
So stop complaining, Dummy!