They have to obtain information from some source. Almost always, that source of information can mislead the reporter/news writer easily because of the latter's lack of familiarity with the issue, the region or the culture. The reporter, on the other hand, works against time. Plus, s/he is, after all, human (susceptible to persuasion/personal biases and worse, is sometimes too lazy to do a fact-check and more importantly, to hear the voices from the other side).
As most things in life, the truth is always in somewhere the middle.