Last night, Bill O'Reilly claimed that “people lie on MSNBC every day.” O'Reilly made the claim as a fact and wondered why anyone would believe what they see and hear on the oh-so-liberal MSNBC. (Not to mention what they read at Media Matters.)

O'Reilly's comment raises a point that has been puzzling me for years, as far-right media critics set their sights on MSNBC for being an alleged liberal bastion of misinformation. (Y'know, that liberal bastion that just banned Markos for making Joe Scarborough upset.)

Here's the riddle: Why don't conservative fact check MSNBC every day and catalog all the supposed lies that the news channel peddles? Listening to partisans such as O'Reilly, the liberal misinformation is practically jumping off the screen at MSNBC, and especially during primetime when the news channels hosts left-leaning anchors. So why don't conservatives detail all the lies and regularly post their findings online?

I mean, that's what we do at Media Matters all day long in terms of the Fox News misinformation. We routinely publish at least a dozen items a day, sometimes twice that, plainly detailing how the right-wing channel distorts the news and spreads propaganda. So why doesn't O'Reilly fact check Rachel Maddow's show every night and detail the lies she tells? Or why doesn't the Weekly Standard, for instance, pitch in and fact check Countdown and call out all the falsehoods host Keith Olbermann and his guests concoct at 8 p.m.?

Why doesn't the right-wing fact check MSNBC? Not just whine about MSNBC, but show conclusively how the cable channel makes up liberal lies.

I'm pretty sure the answer is that nobody on the far-right fact checks the liberal “lies” at MSNBC, and especially during primetime, because MSNBC doesn't routinely broadcast them. Unlike Fox News, MSNBC's programming is not built around fitting as much provably inaccurate information into hour-long broadcasts as is humanly possible. In others words, MSNBC is not in the propaganda business the way Fox News is.

But if O'Reilly thinks I'm wrong, than he ought to fact check MSNBC, starting tonight.