Generally when the media push a narrative, it's not by accident or stupidity, it's for a deliberate reason. As this video shows, it permeates down from the top. "Cui bono" - Who benefits? For what advantage?

The Russian narrative was birthed as a red herring to throw people off the trail that the DNC insiders were the real leakers to Wikileaks. Not the Russians ,not Putin. Julian assange hinted as such when he spoke about the mysterious circumstances of the murdered DNC staffer, and Bernie supporter, Seth Rich.

Who is most likely to know first that corruption exists? Those who work there.
Who is in the best position to leak documents? The staffers.
Look at Bradley/Chelsea Manning as an example.

Seth knew the fix was in against Bernie and had spilled the beans to Wikileaks. He was shot in the back while while walking home, no possessions were stolen. That is the reason why there was a continuing false story blaming Russia, a decoy to muddy the trail of evidence back to the real leakers. What's a better way than to make up a false allegation of conspiracy , but to include your opponent as part of the fiction. Double whammy!