Remarked here:

“A black person is seven times more likely to be killed by another black, than a white person is to be killed by anyone.”

The derivation is as follows.

The overall murder rate is 5.3 per 100,000.[1]
Half — 2.65 — of those victims are black.[2]
Blacks compose 1/8 of the population.
That’s 2.65 murders per 12,500 blacks.
To find the rate per 100,000 blacks, we must multiply 2.65 by 8.
2.65 × 8 = 21.20 murders per 100,000 blacks.

2.65 of the victims are non-black.
Non-blacks compose 7/8 of the population.
That’s 2.65 murders per 87,500 non-blacks.
To find the rate per 100,000 non-blacks, we must multiply 2.65 by 8/7.
2.65 × 8/7 = 3.03 murders per 100,000 non-blacks.

Let us consider D.L. Hughley’s proposition that murder only occurs among the poor.

2/5 of blacks are poor.  1/8 of the population are black.  So poor blacks are 2/5  × 1/8 = 2/40 of the population, or 1/20 or 5%.  5% of 100,000 is 5,000.
1/5 of non-blacks are poor.  7/8 of the population is non-black.  So poor non-blacks are
1/5 × 7/8 = 7/40 of the population, or 17.5%. 17.5% of 100,000 is 17,500.

If murder were solely among poor people,
2.65 murders per 5,000 poor blacks would be 2.65 × 20 = 53 per 100,000 poor blacks.
2.65 murders per 17,500 poor non-blacks would be  2.65 x 40/7 = 15.14 per 100,000 poor non-blacks.

[1]Wikipedia: List of countries by intentional homicide rate

[2]FBI — Table 21 (2016)