"Liberals claim to want to give a hearing to other views," William F. Buckley once observed, "but then are shocked and offended to discover that there are other views." He might have been writing about some of the nation's newsrooms.

Many media establishments obsess over diversity of pigment, while remaining ideologically monochromatic. This produces big blind spots and glaring examples of unconscious bias.

Here is one such example. A recent Wall Street Journal article on bicycle helmet laws began this way: "Helmets help prevent head injuries, so laws requiring cyclists to wear them would seem obvious."

Really? Why?

Helmet laws seem "obvious" only if you take several things as already given: (1) that government should force people to do what is in their own best interest; (2) that government actually can know what is in other people's best interest; and (3) that laws designed to promote people's best interests actually will do so.

The point of the article, however, was to note that cycling advocates take what it calls a "surprising" position: Mandatory helmet laws "make cycling less convenient and seem less safe, thus hindering the larger public-health gains of more people riding bikes. All-ages helmet laws might actually make cycling more dangerous, some cyclists say, by decreasing ridership. Research shows that the more cyclists there are on the road, the fewer crashes there are." It goes on to cite research showing that the reduction in head injuries is offset by increased obesity caused by people not riding, which thus produces "a net negative health impact."

In short, given No. 3 might be wrong: A government program passed with good intentions might have unintended consequences.

Imagine that.

The article doesn't even mention the other two assumptions embedded in the opening sentence, let alone challenge them. But it is not a given that government should force people to do what is in their best interest. Millions of Americans recoil at the very idea. And even if government should, "best interest" means different things to different people. Some individuals want a long, healthy life free of pain and suffering. Others prefer to risk serious injury and even death so they can live a life full of intense thrills from activities such as riding a motorcycle, playing football, skydiving and so on. (Fun fact: The most dangerous high-school sport is actually boys' gymnastics.) On what basis does society conclude one vision of the good life is superior, and not only superior, but so inarguably superior that it should be imposed by force?

Another example: This past Wednesday a Washington Post story opened as follows: "It sounds kind of crazy to say that foreign aid often hurts, rather than helps, poor people in poor countries. Yet that is what Angus Deaton, the newest winner of the Nobel Prize in economics, has argued."

Why does that sound kind of crazy, exactly? The case against foreign aid is clear and straightforward: It props up corrupt governments and impairs economic growth by sabotaging local business, thereby perpetuating a cycle of dependency. And that point has been raised again and again: "Development Aid Harms Development" (American Enterprise Institute, 2004); "Interview with African Economics Expert: 'For God's Sake, Please Stop the Aid!'" (Der Speigel, 2005); "Is Aid to Africa Doing More Harm Than Good?" (NPR, 2007); "Lessons From Haiti; How Food Aid Can Harm" (The Atlantic, 2010); "A Surprising Case Against Foreign Aid" (New York Times, 2013); etc.

You don't have to find the arguments against helmet laws and foreign aid convincing to acknowledge they exist, and are at least plausible—perhaps even plausible enough to require some kind of rebuttal. Yet to reporters and editors at two of the nation's largest newspapers, the arguments were not merely implausible—they were invisible.

These are glaring examples, but not isolated ones. During court challenges to the Affordable Care Act, countless media outlets treated the constitutional arguments against Obamacare as cockamamie nonsense that nobody could take seriously—until those arguments prevailed (as with Hobby Lobby), or nearly prevailed (as with the challenge to the individual mandate), at the Supreme Court.

The nation's media also are in general agreement about the evil inherent in "dark money." That is money given not to political action committees, which must disclose their donors, but to "outside groups" such as the NRA and Planned Parenthood, which do not. Those groups then use that money to express their views about politics, but they do so independently—that is, without consulting the candidates or the parties.

Yet many in the media seem oblivious to certain types of dark-money political involvement. One of the biggest dark-money groups—a powerful corporation long controlled by one of America's richest families—recently blasted the Republican presidential candidates for engaging in "crazy talk" that was "frightening"—filled not just with "lies and exaggerations" but with "assertions so untrue, so bizarre," that they were "surreal." In another blatantly partisan electioneering communication, this powerful corporation warned that America faces a "college affordability crisis. But candidates from only one party are taking it seriously."

"Democrats Offer Ways to Make College Affordable" was the headline on that New York Times editorial. The headline on the first was, of course, "Crazy Talk." If the campaign-finance laws advocated by critics of dark money were applied consistently, the government would forbid newspapers to print such editorials. Funny how so few in the media are concerned about that.

This column originally appeared at the Richmond Times-Dispatch.