It's because national news media have never come to terms with what Martin Luther King Jr. stood for during his final years.
In the early 1960s, when King focused his challenge on legalized racial discrimination in the South, most major media were his allies. Network TV and national publications graphically showed the police dogs and bullwhips and cattle prods used against Southern blacks who sought the right to vote or to eat at a public lunch counter.
But after passage of civil rights acts in 1964 and 1965, King began challenging the nation's fundamental priorities. He maintained that civil rights laws were empty without "human rights" — including economic rights. For people too poor to eat at a restaurant or afford a decent home, King said, anti-discrimination laws were hollow.
Opposition to the Vietnam War. Opposition to poverty. Good stuff.