News media are biased, but the biggest problem isn't the ideological bias that conservatives complain about.
Media are biased in favor of covering a story quickly, because viewers want their news when it's new. Information that comes in later that gives a fuller picture will be discounted accordingly.
Media are biased in favor of presenting a simple dramatic narrative. Complex stories without clear villains and heroes and a clear conclusion are less compelling for the average viewer or reader, and less satisfying for reporters and editors.
Media are biased in favor of stories that can be presented with a compelling visual image.
Media are biased in favor of stories that are cheap to present. Rerunning a video of an incident released first and calling in a pair of talking heads that you can expect to argue with each other is cheap. Sending a real reporter to the scene to find out what actually happened costs more.