The first thing that I have to address, I suppose, is the song's use of a racial slur in the title.  It is, in some sense, "not OK," and yet I have to say that being white I'm more likely to react to it with a snicker than with fear or umbrage at an insult to my dignity.  I understand why he says it.  If you don't, well, maybe this video or lyrics below will offer a hint.

Whitey on the Moon

A rat done bit my sister Nell.
(with Whitey on the moon)
Her face and arms began to swell.
(and Whitey's on the moon)
I can't pay no doctor bill.
(but Whitey's on the moon)
Ten years from now I'll be payin' still.
(while Whitey's on the moon)
The man jus' upped my rent las' night.
('cause Whitey's on the moon)
No hot water, no toilets, no lights.
(but Whitey's on the moon)
I wonder why he's uppi' me?
('cause Whitey's on the moon?)
I wuz already payin' 'im fifty a week.
(with Whitey on the moon)
Taxes takin' my whole damn check,
Junkies makin' me a nervous wreck,
The price of food is goin' up,
An' as if all that shit wuzn't enough:
A rat done bit my sister Nell.
(with Whitey on the moon)
Her face an' arm began to swell.
(but Whitey's on the moon)
Was all that money I made las' year
(for Whitey on the moon?)
How come there ain't no money here?
(Hmm! Whitey's on the moon)
Y'know I jus' 'bout had my fill
(of Whitey on the moon)
I think I'll sen' these doctor bills,
Air. Mail. Special
(to Whitey on the moon)