A few reporters getting duped is NOT the same as intentionally and repeatedly manufacturing fake news. This is actually a strategy of the fake news pushers... try to dress something up well enough to get picked up by the more reputable sources. Then declare them irriputable when one of dozens of false-flag operations gets through. But the point is that this story was (a) discredited by other news sources and (b) will be or already has been retracted by the WP and (c) reporters will lose their jobs or be demoted, not promoted like they would at a fake news operation.
Also, I'm sure that Rolling Stone has been scouring the Washington Post for something poorly sourced like this, since it was the Post that eviscerated Rolling Stone for the expose on gang rape on college campuses, which turned out to be fabricated by the victim (though actually in a very convincing way).
The problem isn't fake news, it's a public who can't pay attention longer than one 24-hour news cycle. The real facts are almost never known within 24 hours. If people drew their conclusions after there had been enough time for consideration and cross-checking, fake news would have no power. Just like superpacs would have no power if people would just not believe a word of what someone paid for them to hear, duh.