First, they just followed trends. In the 80s, that very same media was quite conservative. It’s also because there was a Democrat in the White House and the ‘mainstream’ media generally just parrots what comes out of the White House, be it under Democratic or Republican control, particularly when it comes to foreign policy. What Fox does is not ignorantly parrot White House discourse but instead offer its own ideological discourse in an attempt to influence the White House, and not the other way around. It’s only after Fox News had established itself that the ‘mainstream media’ attempted to copy-paste Fox’s tactics on channels like MSNBC, and particularly with Beck-like morons such as Keith Olbermann and Rachel Maddow. Most of their anchors and news reports, however, still kept parroting White House discourse on things such as the war in Iraq and economic policy.

Second, and more important, even if the media was just parrotting a Democratic White House in the 1990s and since the Obama election, theur views in now way qualify as “left”. Maybe in comparison to the Republicam party it feels like left but then the Republican party is left when compared to the Tea Party Movement. The ‘mainstream’ media has by and large maintained a pro-free market, pro-war discourse that came out of the Clinton and Obama administrations. The question is really how much of a right wing slant will the media have.