It really bugs me the way people fail to distinguish between the two (at least) very different ways in which the term is used.
1. fake news=the political equivalent of military disinformation; highly exaggerated or totally invented "news" items circulated by politicians to inflame their base and/or smear their opposition and/or deflect attention from what is really going on.
2. fake news=a label that constitutes a derogatory attack on reliable and reputable news outlets that are reporting news that the attacker doesn't like and doesn't want widely disseminated; an attempt to invalidate or at least spread insidious doubt.
The invention and widespread use these days of #2 muddies the waters and creates confusion in identifying the numerous instances of #1.