As the fallout continues from the White House's decision to extend the Bush-era tax cuts, including for those on the top end of the earning spectrum, liberal commentators have been expressing their deep frustration and disappointment with Obama:

I'd like to think Olbermann's White House critique last night, which was hardly his first since Obama was inaugurated, will help put an end to the conservative canard that MSNBC is just like Fox News, it just programs to the left.

Except that, of course, it's not.

I raised this same point in August and noted a long list of White House grievances that had been aired on MSNBC, ranging from DADT to the BP oil spill:

MSNBC tees off on Democrats, even during the channel's supposedly liberal, opinionated shows, in the way Fox News absolutely refused to do when Republicans under Bush ran Washington, D.C. (And still refuses to do today.)

It's true -- Fox News and Roger Ailes would never, ever, allow one of its hosts to air detailed complaints about a Republican administration the way MSNBC routinely holds the current Democratic one accountable.

Or you could turn the formula around for today's setting: Fox News and Roger Ailes would never, ever, allow on its hosts to air detailed praise for a Democratic administration. (Have you heard any Fox News applause for Obama's decision to extend Republican tax cuts?)

Fox News employees cannot scold Republicans and they cannot laud Democrats because Fox News adheres to an air-tight political dogma. Because Fox News is in the propaganda business, not the news business.

And that's why MSNBC is not the liberal Fox News.