Not ug related but culture related question (to black ppl)

Why saying the n word while rapping/singing/quoting lyrics is considered racist from non black ppl?? I get the word has a lot of vitriol especially when white guys use it,but I have seen insane double standards in this situation. Guys like eminem and serj tankian have openly said this word and not really got cancelled/called out but kpop idols who have rapped/sang a song with n word they get flamed really badly. I also see black folks allowing Mexicans/indians say it so ts is confusing.

Also as an Indian, I always thought u could rap to songs w n word and it meant another way of saying brother but only when I turned plder I’ve realised the actual history of it

Ik yall will think I want to say the word so bad but that’s not really want i want i wanna understand different opinions from black ppl on this topic because honestly idk now i feel very bad even singing along to music with N word in recent times.