Your usage, "I'm as hateful as" wouldn't be as powerful.
The literary device that brings power to that line is Irony.
It is ironic because Blacks were one of the groups that didn't face extermination at the hands of Hitler.
It is ironic because of the tension between Blacks and Jews in America that he references the race that persecuted the Jews(who dominate the power positions in the music industry). A persecution that they are keen, and systematic on reminding everyone of, while Black history gets largely ignored and written out of the books.
It is ironic because the skin is an extremely visible condition while the heart cannot be seen until someone is dead. It is easy to fake having a good heart, it is not easy to fake your skin color.
It is ironic because he is taking this condition that has been caste as a negative (black skin) and setting it as a positive in contrast with something that is an actual evil (aryan genocide).
And you said black heart doesn't create a clear image for you so I'ma help you out.
Dis a regular heart
das a black heart (probably in a NAZI).
He also uses synesthesia
"In literature, synesthesia refers to a technique adopted by writers to present ideas, characters or places in such a manner that they appeal to more than one senses like hearing, seeing, smell etc. at a given time."
He is using a color (visual) to convey pain (sensory).
These are highly advanced and abstract concepts. Not quotable nonsensicals like:
Gold grills like a set of new braces's
[SPOILER]
Kevin Gates >Kendrick anyway
[/SPOILER]