Why was Juan Williams fired?

NPR's statement as to why Juan Williams was fired:

On Wednesday night we gave Juan Williams notice that we are terminating his contract as a Senior News Analyst for NPR News.

Juan has been a valuable contributor to NPR and public radio for many years and we did not make this decision lightly or without regret. However, his remarks on The O'Reilly Factor this past Monday were inconsistent with our editorial standards and practices, and undermined his credibility as a news analyst with NPR.

Williams made some comments while speaking with Fox personality Bill O'Reilly to the effect that flying with obvious Muslims present made him nervous.  Thus the question naturally springs to mind:  With what NPR editorial standard/practice did Williams' action prove inconsistent?

The hunt is on.

Hey, I think I found the relevant portion (bold emphasis added):

III. Statement of principles
Our coverage must be fair, unbiased, accurate, complete and honest. As NPR journalists, we are expected to conduct ourselves in a manner that leaves no question about our independence and fairness.

Unfortunately, the firing of Williams gives rise to questions about NPR's independence and fairness.  Thus, those who fired Williams need to be fired.  And those who fired those who fire Williams likewise need to be fired since that action will doubtless cause questions about independence and fairness.  And so on.

Goodbye, NPR.

Seriously, though.  If only it was the case that NPR places itself in a catch-22 with this policy.  This is the type of policy that, in real life, is used to get rid of people you don't want.  Those you do want will be excused from compliance.  If it was a serious policy then public polling that reliably indicated that the public perceives NPR as a biased network would show the entire operation afoul of its editorial policies.