It's discussed quite a bit in Manufacturing Consent, with many many examples given - in those days, the U.S. war with Iraq featuring prominently in examples of how broadcast and print media behaved.
There are actually at least two persons who downvoted you because I upvoted the comment above and I see you are still in grey :-D
Complaining about downvotes is however not OK here according to the rules.
Sometimes when I am really confused I ask politely why something I wrote was downvoted, but more importantly I got used to it and get over it. In fact I wonder if I have collected most downvotes (and later upvotes) on my most important comments :-)
It's strange - I'm OK being downvoted if I have a poor argument, am mean (and I'm not), or make a factual mistake.
People vote based on whether they agree or disagree with a political opinion (and is mentioning Manufacturing Consent so partisan in the first place?). I tend to upvote or downvote based on argument strength even if I disagree or agree with the generalized point of view.
That's my philosophy. So it makes me slightly bitter when people downvote 'just because.'
I've recognized this happening but I have never had a word for it until now.