Then why do companies like CNN repeatedly write such poorly researched, poorly documented, poorly verified stories
In general terms, this is happens to any news organization.
requiring frequent corrections, retractions, and dismissals of offenders?
This is where you are mislead, they are not frequent. Still, you picket CNN as your example. There are much better journalistic organizations. Like NYT. Like The Atlantic. What does Right has that still could be called journalism?