The world is a complex place and its very difficult to convey all the available information on any issue. Explaining the context, accuracy, probability and every other factor involved in a point of view is nigh on impossible and not even useful if you are trying to convince someone of your argument. So the simplification of your message can easily sully the vast and complex 'truth'.
I suggest that mechanisms for gleaning the truth are important to democracy and that advertising standards and the legal system, both have roles to play both in clarifying what is true and as a deterrent to those who may be casual with facts.
However, misconception will never be eliminated. Debates and competition between ideas are just as important in keeping democracy clean.