It’s been 50 years since Dr. Martin Luther King, Jr. was shot to death on a motel balcony in Memphis, Tennessee, and over the decades he has become one of the most revered figures in American history. There is an impressive memorial to him in Washington, DC, and a museum celebrating his life in Atlanta, Georgia. Countless schools and boulevards have been named after him, and a national holiday is dedicated to his memory.

How is it, then, that so much of his legacy—what he hoped to pass on to the future—has been lost?

King wanted equality under the law and said, famously, that people ought to judge one another based on character, not skin color. But he also believed that blacks had an important role to play in their own advancement.

The black civil rights battles in America are now over, and King’s side won. The best indication of that may be that King has had no real successor. If black Americans were still faced with legitimate threats to civil rights—such as legal discrimination or voter disenfranchisement—it’s likely that leaders of King’s caliber would have emerged to carry on the fight. Instead, what we have today are pretenders who have turned the civil rights movement into an industry, if not a racket.

And what have these racketeers accomplished? A lot for themselves, and very little for their constituents. Racial gaps in income, education, and home ownership were narrowing in the 1940s, ‘50s and '60s. But after King was replaced as the spokesman for black America by the likes of Jesse Jackson, Al Sharpton and others, these gaps began to widen in the 1970s, '80s and '90s.

This suggests that the racial disparities that continue today aren’t driven by whatever racism that still exists, despite all the claims to the contrary from progressives and their allies in the media. It also suggests that black culture—attitudes toward marriage, education, work and the rule of law—plays a much larger role than the left wants to acknowledge.

More marches won’t address fatherless homes. More sit-ins won’t lower black crime rates or narrow the school achievement gap. Electing more black politicians and appointing more black government officials can’t compensate for these cultural deficiencies, either. Black mayors, congressmen, senators, police chiefs and school superintendents have become commonplace since the 1970s. Even the election of a black president—twice—failed to close the racial divide in many key measures. Black-white differences in poverty, home ownership, and incomes all grew wider under President Obama.

Discussion of antisocial behavior in poor black communities, let alone the possibility that it plays a significant role in racial inequality, has become another casualty of the post-'60s era.

King and other black leaders at the time spoke openly about the need for more responsible behavior. After remarking on the disproportionately high inner-city crime rates, King told a black congregation in St. Louis that “We’ve got to do something about our moral standards. We know that there are many things wrong in the white world,” he said, “but there are many things wrong in the black world, too. We can’t keep on blaming the white man. There are things we must do for ourselves.”

The pretenders to King’s legacy mostly ignore this advice, preferring instead to keep the onus on whites. Where King tried to instill the importance of personal responsibility and self-determination, his counterparts today spend more time making excuses for counterproductive behavior and dismissing any criticism of it as racist.

Activists who long ago abandoned King’s colorblind standard, which was the basis for the landmark civil-rights laws enacted in the 1960s, tell young black Americans today that they are victims, first and foremost. White society is against you, they say, even if you have no clear examples of discrimination to point to. They are told that fire hoses and poll taxes have been replaced by unconscious racism, white privilege and microaggressions.

A generation of blacks who have more opportunity than any previous generation are being taught that America offers them little more than bigoted teachers, biased employers and trigger-happy cops. It’s not only a lie, but as King understood, it’s also self-destructive.

Black activists and white progressives stress racism because it serves their own interests, not because it actually improves the station of blacks. But this neglect of the role that blacks must themselves play in righting their own lives can only make matters worse.

A half-century after King’s death, plenty of people are paying him lip service. Far too few are following his example.

I’m Jason Riley, of the Manhattan Institute, for Prager University.