That's not the connotation of 'fake news.'
Fake news implies that there is a systematic effort to purport fake stories which perpetuate a specific ideology.
This can be FOX News, CNN, MSNBC, etc.
But that's the point. People who don't believe in "fake news" aren't saying that there has never been a false/questionable article in the history of ever. They're saying that the "champagne liberal" boogeyman is not trying to propel its own agenda through staged news stories (at least, not at a systematic level).
There are corporate media outlets, yes, and some are liberal and some are conservative, but they very often also tell the truth (even if skewed by sensationalism).