They probably did too much but it's mainly the fault of the masses for thinking some kind of political revolt was necessary in the form of Trump. We can't blame liberal media for underestimating the levels of bigotry that are within people.
It doesn't help that this campaign became them attacking each other for things in the past. Toss in a bit of misogyny and well...
I would say that the 80% liberal media and 90% liberal celebs turn people off and they don't like a candidate being shoved down their throat. I mean, last night CNN is referring to Clinton as "we need this state to win" etc. Journalists are so embarassing nowadays. Glad their medium is on hard times tbh. They do next to no quality work and are extremely biased.