The MSM still carries a lot of weight with a high percentage of Americans. John Kerry didn't draw the same level of cult-like following like Obama has. He's taken it to a new level.
No doubt they can dampen down a story, but in the end, they must carry it or lose all cred. Kerry’s story in 1971 compared to his race tells the tale. The MSM wanted to help him just as much the last time around, and tried to ignore the story, but they couldn’t.