Earlier quoted context omitted.
I think that the syntactic structure makes it pretty clear that "they" refers to the voters.
i think i was unclear in what i meant - who are the people telling the voters what to do?
It is also clear who is telling the media what to say.
The one thing that is not clear at all is how much the media actually influence voters. I don't think there's as much influence as the OP was trying to convey, but well, as I said, this is not clear.