For what it's worth, if a reasonable person can make a compelling case that a story is not fake news (i.e. if it is "arguable"), doesn't the question of whether it is "fake" or not boil down to a reader's inherent bias (an opinion, which is by definition not fake)?

Also, why not use a white list that includes outlets that sizable portions of facebook's user base seem to think are reliable? For example, include breitbart.com and motherjones.com, but exclude .tumblr.com and .wordpress.com.