Erstwhile veep candidate-cum-pundit-for-hire Sarah Palin recently challenged news organizations to stop "pretending" to be objective and owe up to their alleged left-wing political inclinations, calling out Politico and CNN by name, but apparently referring to the entire industry, that vast, undifferentiated blob of commentary and reportage she consistently calls the "lamestream" media. This is not a new complaint. For years now, I've been hearing that my profession is somehow in the tank for liberal politicians, and is actively working to advance a progressive agenda. And for years now, I've been trying to reconcile this imagined media with what I've learned about actual journalists and newsrooms.I'll concede part of Palin's argument: in our personal views, we journos do tend to tack further to the political left on many issues; opinion surveys by reputable pollsters reveal as much. Shooting the breeze over after-work beers, the reporters and editors I've known usually sound more Rachel Maddow than Bill O'Reilly on everything from the Affordable Care Act to gun control to gay rights.But to assume that the opinions aired by a reporter at happy hour color her approach to her job the following day reveals a fundamental misunderstanding about how the news business -- emphasis on the word "business" -- operates.