For far too long the mainstream media has claimed to represent news and information in an unbiased and fair method. This is entirely false. Even when they own both sources that focus on different political demographics, they still create the boundaries and dialogues by creating the narrative that both sides should support.
This is the framework for how political ideals are moved through the public eye and kept in check. As a business they capitalize on human nature by exploiting humanities biggest weakness: FEAR. Using stories that instill fear into peoples lives they can effectually manipulate the masses through social psychology. This however should not be misconstrued into believing that the MSM will use any fear-based story they come across as an opportunity to sell more papers. There is a very specific way of targeting the fears of demographics into being emboldened not only by their fear, but by the narrative supplied for their fear. Most people do not want to believe that a game has been played on them, and they do not want to live constantly afraid of things they don't understand. Therefore it is in the benefit of the news agency to play into what people already believed and were waiting on proof to declare.
What most have started to realize is that the media plays on our illogical emotional faculties in order to propagate "politically correct" narratives. None of which can truly be an accurate portrayal of reality because they are all presented through a demographically filtered lense. The one you like will convince you that you were right all along, and the one you don't like says you're an idiot. Both of which are payed for by the same mega corporations who intend to use those narratives to their benefit. Since they own both sides, they decide what each side talks about, and anyone who doesn't fit into those two schools of thought are cast aside as fringe, or insignificant. The truth is not always popular. The biggest takeaway from this, is that any news source that makes most of its money from advertising shouldn't be considered unbiased because they have loyalty to their advertisers, but not loyalty to the readers.
(Additional information of the government influence on journalists, see Operation Mockingbird.)
Below is an amazing info-graphic created by designers at http://frugaldad.com/. It illustrates just how consolidated all of our news and information has become.
Aside from the inherent bias, they repeatedly show traumatic events, describing what happened, who did it, and why. This puts more attention on the aggressor rather than the victim and in relation to mass-murder, it tends to inspire copy-cat killers who share similar mindsets. They are tired of being forgotten, and they see an opportunity to always be remembered and take a one way ticket out of their hell. All they have to do is something as bad, if not more terrible and their picture will be on the TV for 24 hour live coverage detailing his every written memory.
The media understands the psychology of why most humans are drawn to tragedy and use it to encourage us to watch about the devastating event while they capitalize on the crisis.