Rallying against objectively "fake" news doesn't do anything about the much more serious problem of the way that mainstream news is less than truthful in more subtle ways, such as under-reporting or not reporting things that are true, emphasizing certain facets of a true story to follow a crafted narrative, reporting on things that otherwise wouldn't be newsworthy to advance that narrative, etc. Disproving blatantly fake news is trivial, disproving years of propagandizing full of half-truths and consistent narratives is impossible.