I would never suggest that what is now called “the mainstream media” — the news organizations that most Americans depended on over the past century — achieved a golden mean. We have too often been condescending to those who don’t share our secular urban vantage point. We are too easily seduced by access. We can be credulous. (It’s also true that we have sometimes been too evenhanded, giving equal time to arguments that fail a simple fact-check.)

But we try to live by a code, a discipline, that tells us to set aside our personal biases, to test not only facts but the way they add up, to seek out the dissenters and let them make their best case, to show our work. We write unsparing articles about public figures of every stripe — even, sometimes, about ourselves. When we screw up — and we do — we are obliged to own up to our mistakes and correct them.

Fox does not live by that code. (Especially the last part. In a speech at the University of North Carolina last month, Ailes boasted, “In 15 years, we have never taken a story down because we got it wrong.” Gosh, even the pope only claims to be infallible on special occasions.) For a salient point of reference, compare Fox’s soft-pedaling of the Murdoch troubles with the far more prominent coverage in The Wall Street Journal, which has managed under Murdoch’s ownership to retain its serious-journalism DNA.

Why does this matter? In the digital era of do-it-yourself news consumption, it is easier than ever to assemble an information diet that simply confirms your prejudices.