Why do people always blame the parents?

I'm so sick of people assuming that because a child is acting like a demon, it's automatically the parents fault. No one can control what their child does 24/7! I'm sixteen years old, but I know that if I do something wrong, it's not my mother or father's fault. Or if something controversial gets out in the media like the Glee GQ photos, kids watching Family Guy, Miley smoking the bong, the media cops out and says "Well, it's not our fault that you let your kids watch that stuff. Get parental block. We're not telling them to do what we do." Yeah, because parents are. Instead of owning up to their mistakes, the media turns it around the parents when parents start concern over their child. I mean I can be a spoiled kid, but don't bring the people who cared and raised me into this.