You can choose to try to share something but they will ignore it, on purpose. There are too many reasons to list why (R)s do it, most of it is mental illness.
Propaganda is another feature in public discourse, it's been used so well for 100 years it's an art form now, most people can't even tell what is or isn't propaganda. For instance, here's a definition of propaganda, note that if your insert "news" in place of "propaganda" there's no difference in today's media:
http://en.wikipedia.org/wiki/Propaganda
---Propaganda is a form of communication that is aimed at influencing the attitude of a community toward some cause or position. Propaganda is usually repeated and dispersed over a wide variety of media in order to create the chosen result in audience attitudes.
As opposed to impartially providing information, propaganda, in its most basic sense, presents information primarily to influence an audience. Propaganda often presents facts selectively (thus possibly lying by omission) to encourage a particular synthesis, or uses loaded messages to produce an emotional rather than rational response to the information presented. The desired result is a change of the attitude toward the subject in the target audience to further a political agenda. Propaganda can be used as a form of political warfare.---