Why does the mainstream media cover Casey Anthony all day long and avoid real stories?

You can't turn on a TV w/out hearing about that d*mn Casey Anthony case, but the Marine in Arizona that was murdered by a swat team can barely get a 30 second segment on any news station (except local). Is it racial? Is it because the media doesn't like to bring up the injustices of our police/military forces? I don't get it. Why don't they cover real stories that actually could make a difference in our lives. Is it really just pure propaganda...