Why is rap lyrics so bad and contains errors?

Rap is a music form of Afro origin and it is in the form of venting out vexed feelings. Lyrics need to be in a flow to bind well with the music and the rhyming scheme so it cannot be expected to be grammatically correct.

Rapid mumbo-jumbo is as talented as walking in a straight line whilst chewing gum. The POINT of it is to be clannish, laddish and make tons of DOSH for supposed heroes in the ghettos, rabbiting TOSH.

NO racism implied - it's CULCHA MATTER - as passing a phase as GLAM rock, PUNK and other abominations. Culture is enshrined in Language and the more these RAPPERS mutter, utter NONsense, the more they separate their followers from main-stream. One assumes Eminem is simply illustating others can do it just as well - climbing on the samed cash band-wagon.

Rap is the best music genre for lyrical meaning/complexity.. Check your own grammar you illiterate fool

Just because it doesn't fit your warped grammar, doesn't mean it has errors. Check yo selfbefore you wreck yourself.

If you were concerned about grammar you should consider revising the question you have written.