Unless people are caught red-handed fabricating those, how can you know it's fake? You think that cross-referencing or having "reliable sources" like Wikipedia will help you
know what's going on on the other side of world (e.g Ukraine/Russia)? It's probable even the people in the involved countries don't truly know what's going on.
The only facts are what I can perceive with my own senses and what comes directly from people I know enough to have a judgment I consider reliable on their trustworthiness.
Fact is that entities using the expression fake news are often not better than the ones they accuse.