This has nothing to do really with rap, the guy is simply one of those "I can do whatever I want" assholes.
I used to have a neighbor who would blast salsa music at all hours, my landlord told the guy to knock it off or else.
He told my landlord to fuck off and threatened him.
Next day some of his relatives were there, moving the guy out since he was in jail.
I've lost count of the number of times I've heard all sorts of "music" and music being blasted from cars, while I'm on my bicycle.
Sounds like the rap-blasting neighbor just wants to inflict his choices on everyone.
That's what the cops are for.
I'm typing this while listening to Mozart.