The mainstream media in many countries is heavily biased to the left - probably because people think you need to go to University to become a journalist, where people are then influenced by Neo-Marxist leftist professors and faculty.
The mass sexual assaults in Cologne during 2015 NYE - the mainstream media deliberately didn't report that until two days after the event!
Plus you have situations like Sweden deliberately not collecting the ethnicity of criminals in their statistics, so as not to paint a pretty picture.
Even on many subreddits, news which paints migrants in a bad light is deleted by moderators. The news that South Africa would seize White farms was deleted by many moderators on popular news subreddits.
Facebook is the only source left in many cases.