I'm assuming the "fuck you" was the one that fired her. However you choose to understand free speech, being needlessly rude as a media representative of a company should get you fired.
(Curiously, I've just seen someone walk past me with "duck off" printed on their T-shirt. But then, culture here in Germany is much more liberal about both word and deed — it's American cultural norms that made the autocorrupt inside my quote marks).