The mainstream media's power is that if they find the message distasteful, they prevent the message from being presented.
This is known as the 'shoot the messenger' school of journalism.
Here's an example from Boston about the public being kept in the dark about the terrorist threat around them, and also assault on free speech in America.
Read the story here.
The Boston Globe versus Free Speech:
ultimate victims here are the people of New England, who are kept
ignorant of the potential dangers in their community. Welcome to the New
Journalism -- serving private ideology against the public interest."