They are largely to blame. Ask yourself where your own misconceptions came from before you found out for yourself? I know that's where mine came from. You believe what you're told in newspapers or on the news on the television, as often that is your only point of reference and then when politicians say the same thing, why would you question it?
That's it! If you only ever hear one side of a story how are you to know about the other side?
Sensationalism editorial bias in the mass media is the biggest cause of this misconception IMO