More Liberal journalists ≠ Liberal bias in media. MSNBC and CNN, for example, probably staff more writers than Fox News. Since you can’t watch two at the same time and we know those two reach about the same number of eyeballs combined as Fox News does, the higher number of liberal journalists doesn’t result in a more liberal cable news environment.
Likewise, the NYT and WaPo probably have the largest staffs of the online/print news outlets (obviously, cable news spills over online, too). But print newspapers are dying or already dead. They’re actually competing in the online space, where you don’t have to look far or hard to find Right wing websites that are well-funded, and well-advertised, while perhaps employing fewer writers. Since people seek out the news sources they want, the argument that internet news sources are more Liberally biased is a dubious one. It’s a more or less equal playing field.
And then there’s the matter of jobs that actually get to dictate what news is covered and how. Local news networks tend to be politically agnostic because they know they can’t afford to alienate a subset of viewers. Local news broadcasts are much more matter-of-fact than other news broadcasts. Very little opinion airtime. Anchors count as journalists, but they’re told what to say rather than deciding what they say. So they could be Liberal but it doesn’t matter because they don’t make programming choices and don’t get opinion pieces. Same with field reporters. They count as journalists but they’re just going to car accidents, or protests, or the local farmers market and reporting on the events in front of them. There’s very little leeway to allow political opinion in.