Why white people shouldn't use the word nigga

I have always wondered why a white person would want to use the word nigga because I felt most say it being a wise ass, think it's cool. so I asked a couple.  I  came across the same couple of answers. "It's in the music so I want to say it" and "Black people say it all the time." The stereotypes depict Black Americans as lazy, gang banging criminals who don't take care of there kids but I don't see anybody trying to copy any of that. And that has nothing to do with my point so I digress...I've heard a white person say they drop the "er" when they say it. The fact that you have to think about dropping the "er" is a reason why you shouldn't say it. there are many different ways to use the word nigga, depending on your tone and how you emphasize the word it can mean many of things but it flows. Someone who grew up around niggas don't have to think how they should say it or did they say it right. Another reason is white people think only Black Americans can be niggas. I use to work with this White women at this DVD warehouse and we were sorting on the line, we'd read the movie cases when the line was down. I forget the name of the movie but it was a gay love story and it had two White guys on the cover and I turned to her and said "They got a gay nigga movie" and chuckled might I add she had made her case to use the word and would say it in front of me around to her White friends and that's why her answer had me baffled, she said "those ain't niggas those are white boys"
"naw dem niggas I said"
she repeated "those are white boys"
"anybody can be a nigga to me, when the time is right."
 at that point I quit letting her say it around me. If somebody doing a slow ass right turn as I'm trying to make a left on a yellow light, I don't look to see if it's a black person before I yell "dis nigga" cause it's usually a white person but he a nigga now cause I'm already two minutes late for work!