"First Amendment?" Do you folks mind if a law student rants about the First Amendment for a minute? Great, thanks.
The First Amendment doesn't protect Punk here. The whole point of the First Amendment is that the GOVERNMENT won't prevent you from speaking. The First Amendment doesn't protect you from the public backlash to your words; quite the opposite! It invites the public to listen and respond to anyone who expresses himself. And furthermore, it doesn't protect someone from his employer, especially when the employer has a legitimate business interest in shutting you up. Whenever you hear some blueberry like Sarah Palin saying that a radio host's First Amendment rights were violated, just imagine kicking her in the vagina.
/rant