Language is rarely, if ever, neutral. Words come to have meaning through historical and cultural legacies. A word that invokes a strong negative reaction in North America might not mean anything particularly provocative in another country. Words are largely context-dependent.
The word slut has a long history in the United States - a product of chattel slavery and white mens' concerns over black female 'promiscuity'. Instead of delving further into this history and the implications for black women myself, I'm going to direct everyone to an article written by the Black Women's Blueprint. They are an intersectional activist group based in Brooklyn, NY. They say it all. I encourage everyone to read it. And thanks to my friend Apu for sharing the link!
http://www.blackwomensblueprint.org/2011/09/23/an-open-letter-from-black-women-to-the-slutwalk/