Sowell is arguing that black people were better off in the first half of this century in terms of "common decency" (whatever that means). Then liberal policies came along and.... destroyed the black community. That's basically what his argument boils down to... I'm sarcastically pointing out that he is wrong. Black people are better off by most measures than they were in the 1940s when they were marginalized and completely shut off from fully participating in society.
Sowell tries to paint a rosy picture of the first half of this century by making baseless claims like "
Back then, no one worried about being mugged" 
A look at crime rates in the 1920s and 1930s would show that he is completely wrong. As of 2011, homicide rates were lower than in 1950. The high incarceration of blacks today can be directly traced to the bogus war on drugs which ironically was motivated by the fear of black men.
" this notion that you have to be afraid of the cops, they’re out to get you and so forth, there was nothing of that sort." 
Yeah black people didn't fear the cops even with the high rates of hangings in the south which were implicitly or explicitly allowed by law enforcement and the courts. Yeah black people were best friends with the cops and Ferguson like incidents never happened.
But history doesn't matter much to the likes of Thomas Sowell unless he wants to bash social programs that he doesn't agree with. The fact that he argues 350 years of slavery, failed reconstruction, Jim Crow have had less an impact on black communities today than welfare legislation passed in the 60s is just laughable.
Thomas Sowell is the type of defeated black man that will go to any lengths to defend the power structure and make excuses for atrocities committed against black people in the history of this country.