Jonathan Chait of New York Magazine nails it:
It’s obviously true that political campaigns will take their opponents’ statements out of context. That is probably unavoidable. The key step I’m focusing on here is when the journalist internalizes the work of the oppo researcher. Perhaps, in the end, the dumbest, least fair, most context-free interpretation of the line will ultimately prevail. But when journalists assume this will happen and make no effort to fight against that process, we go from merely reporting on the stupidity of politics to becoming accomplices of it.
This is the kind of awful coverage that is the vast majority of how journalists report on politics in my country: a weird meta-politics that tries to prognosticate on what political measures are popular amongst the hoi polloi instead of forming a personal, informed opinion on a subject.
It creates an echo chamber of Etch-a-Sketch memes that come and go with a public that is none the wiser for it. The Daily Show did a great bit on it recently.