They did this previously. The problem was that this disqualifies most news outlets operating on the fringes of reality. Since this includes most of the favorite news sources of tea-partiers it obviously can't stand. I don't particularly like the Democratic party, but any news site labeling itself as "right wing news" is for nutters. Facebook censored those sites and the nutters got angry and that's how we got here.
Google News covers plenty of "right wing" news. One can only think FB is intentionally letting quality fall in order to show they really had to do something.