(1) Description of the pattern
Words are powerful, and the stories they make can destroy governments. Dissenting voices must be silenced to maintain order and discipline. The voices of the oppressed carry an emotional appeal far stronger than that of any government sanctioned media, therefore governments will censor those that cause them harm.
(2) Why the pattern is good (i.e. bad)
Dissenting voices are powerful forces for change. If those in power wish to maintain control over societies and cultural movements, they must silence the voices and ideas of those that wish to change the systems of power. Within many dictatorships the control of ideas within the media and internet are integral to maintaining power. If these voices were able to speak freely, people would become interested in their ideas and begin to think in ways that may contradict those in power, which could lead to a revolution.