The biggest issue is that the media is owned by the oligarchy, and so as you note any opinions that fall outside the accepted norm are ignored. This completely perverts democracy as unbiased media is crucial to having informed public that can vote meaningfully. It's simply not realistic to expect individuals to do their own research and become experts on many different subjects in order to vote because any individual subject can take years of study to grasp properly. The job of the journalists is to do this research for the benefit of the public and then present it in a way that's meaningful to the layman. When the media stops doing its job democracy dies.