I might miss the mark here, but you are dead on. Obama has not totally undercut the Constitution regarding Free Speech - yet. Bill Plante, and the rest of the media, are perfectly free to launch a continuing critique of the President, his appointees, his policies, and everything else that he does or says. But, they won't. It is self censorship that Plante and his cohorts have practiced. It is THEY, and not Obama, who have stifled their First Amendment rights in the name of the liberal collective.
My Dear Mr. Plante - you may begin exercising your First Amendment rights at any time you choose.