Well. It's a magic circle, in a way.
You made a point that the press just makes money. Thus, to get more money, they have to publish facts and comments as close as possible to the opinions of their readers. But where do readers' opinion come from?
I'd say from the press and media.
I've studied
PR techniques and know what one can juggle the public opinion in any way he wants, provided he has access to a broad auditory.
There are funds reserved for
PR in budgets of nearly all major companies. So they are in politics.
If you want to raise some cash, you just need to publish such things as ads or biased articles in favour of those who pays you.
In order to bring people's attention to some fact, some journalist is provided with some information and he creates a sensation. People's interest gets warmer and they demand more facts. Each new publication leads readers away from some other "inconvenient" fact.
At that, the "facts" that were published could fail to pass any close examination but that doesn't matter because the harm has already been done which had been the initial goal right from the beginning. Public opinion has already been formed up and people who read tabloids don't bother themselves with checking whether the facts they read about are true or false.