This relates to the fallacy Appeal to Anger. Like all Appeals to Emotion, it’s perfectly fair to express your opinions and feelings; it’s a fallacy only if you fail to provide any logical reasons. Politicians have always used Appeal to Anger because it’s a proven way to motivate voters to act. Today’s media pundits and social media accelerate this even more. They may only be acting outraged, but more often they amp themselves up to believe their own outrage. Either way it lacks authenticity, but it is still highly effective on their audiences.