The main problem with fake news is that many journalists care more about supporting a narrative than about describing reality. Some even believe that reality is a social construct. This makes the consensus world views very brittle and susceptible to enemy (or random!) propaganda.
Because they lack an epistemological baseline: they don't assign confidences among ALL possible models according to hard evidence (and remain agnostic about the rest). Their world view is grounded in the beliefs of others (Kegan lvl 3).