I just want to start off by saying, that this post is mostly going to be conjecture. The above claim is a very strong claim about an institution that would never ever openly admit to it. So any "evidence" that is out there to support this would be based on piecing together things we already know. And even then, correlation does not equal causation. This does not mean that the claim can't be true, but that unless you're an insider getting such information would be impossible to obtain. But there is a lot of known information that make a strong case for black ghetto culture being mostly engineered.
Secondly I want to make the distinction. I believe the CIA largely influenced the creation of black ghetto culture. I do not believe it was the intention. I believe black ghetto culture was an unintended consequence of the CIA meddling.
1910-1970s: Why the CIA felt it needed to step in
During the cold war, communistic and socialistic ideals were growing among the youth. This was especially true among black students, who started to embrace ideas of marxism in their real struggles in a racist America. There were many organizations that were started by communist, the NAACP being a popular example in the 1900s, but in the 1950s the Black Pantheer Party was another big example of this. In efforts to destabalize the US economy, and possibly cause the USA to implode, it is often alleged that many communist started to find unity with Black Americans. And this means a rising sentiment and sympathy towards the socialism.
After the 1970s, with a huge economic downturn, and strong black middle class cities now moving into incredible poverty, anger towards the USA was more pronounced. Large black manufacturing cities like Detroit and Oakland saw their neighborhoods turn poor due to jobs leaving their communities. This lead to many blacks entering the black market, with prostitution and heroin dealing becoming big. Even back then, there wasn't a large embrace towards "thug culture" in the black community. And actually most of the mainstream black community largely shunned the idea of pimps and hustlers.
However many community leaders were still around, and many grassroot organizations like the crips and the bloods. Many of these were organizations to reduce violence in the communities, and protect each hood against drug dealers and pimps. These gangs were based on each block, and were protectors of each and every block. These organizations started to find alignment with the Black Panther Party, which was socialist and considered an enemy of the state.
So looking at this strategically, what would have happened if Russians started to arm black Americans who were aligned with socialism? Well a major amount of civil unrest would occur, and this would give the Russians a decisive advantage in the cold war.
1980s: The creation of the ghetto economy
While heroin, cocaine, and other narcotics have been popular in the black community, for the most part it was only considered something for low lives in the black community. Due to a larger family structure, many black youth were heavily discouraged from these lifestyles. But by the 1980s, after a decade of heavy welfare, which gave an incentive for black women to kick black fathers out of the house. The 1980s was the realizations of a fatherless society, and the rise of matriarchy in the black community. With jobs in the inner city becoming more scarce, banks not willing to fund the creation of black businesses, and severe economic depression, more and more people started to turn to drugs. But there was no more addictive drug than crack.
Crack was engineered to be probably one of the most addictive substances alive. And it was super super cheap to cook. In 1980s, crack flooded the streets of the USA. And the CIA supplied it. The incentive "starve out the black economy". The CIA created incentives for banks not to loan to black businesses, causing massive amounts of black unemployment. And on top of that they supplied gangs with crack and guns. Simple wars between street gangs now became deadly arm races for a limited quantity of crack.
It's simple economic planning. You starve an economy, create demand, then you drop in the most addictive substance known to man, and you create an economy based on drugs. And with that, we got what was the first example of black ghetto culture. Not only were drug dealers making insane amounts of money which made them rich in their own ghettos, but they were the only examples of successful black people most kids grew up seeing. There was all of the incentive in the world to enter the drug game. But still in the 1980s, no one REALLY worshiped drug dealers. For the most part everyone was scared of them, and no one actually encouraged it. So how did black people come to embrace "hood culture en mass"?
Rap goes mainstream, and gangsta rap leads the charge
To ensure a culture of ignorance, the government needed to reinforce ignorant role models. And the best way to reach out to the youth was through rap. It is definitely no coicidence that rap started to find it's mainstream appeal when every rap was a gangster, only talking about gangster lifestyle with no actual "moral to the story". Now it was cool to embrace senseless violence. And gangster rappers now became the latest examples of black millionaires, becoming some of the richest black people to exist in history. The image of gangsterism was something that every black kid needed to inspire to be. So what was necessary was to embrace a culture of ignorance, put nothing but images of ignorant black people on TV, and downplay any black person who was successful without the need to be an entertainer.
TL;DR
In an effort not to lose the cold war, the CIA needed to create confusion in the black community. Blacks being organized would have meant that Russians could have taken over. So the key was for the US Government to make it impossible for blacks to start business (in essence taking away possible income streams), create a depressed economic environment, and then artificially create demand by putting addictive substances on the street. And then flood all mainstream black music with ignorant images so that the idea of being a stupid ignorant gangster is a cultural norm.