[Chyzwar]

Because he is silly. Pravda is similar to Polish word Prawda than means truth. Truth is very difficult to establish outside science.

  - People are biased in many different ways.
  - Modern propaganda can use true facts to build any public perception. 
  - You can have contradictory facts about same events
  - Cognitive dissonance has the stronger effect than people think.
  - Sometimes lies are needed because the truth is not something people can deal with
  - Perspective is different between genders/race/religion etc

An incredibly difficult social problem not technical. Wikipedia tries to build a system like that and it far from a success.