Oooh, aren't we testy!
The MOONBAT refers to anyone stupid enough to wear a T-Shirt that's "in your face" to cops that are probably a bit annoyed anyway.
As for unconstitutional, I doubt it. There's no constitutional right to get on a subway, therefore those who ride are subject to whatever security those who own it dream up.
Irrelevant. It's the searches that are unreasonable, because they are random. Others are not stopped for a search. Probably a equal protection clause violation, as well.
Are you suggesting it's reasonable to deny a citizen access to the subway just because of the t-shirt they're wearing?