The B-word and the N-word

Listening to rap music, I was singing along when my partner pointed out to me that when they used the N-word I left a gap in the song, but when they used the B-word I didn't. I continued singing, this time using both the B-word and the N-word, no gaps.

The song ended on the N-word, at which point I looked over at her and smiled. She said, "oh, don't smile, all that proves to me is that you're more sexist than you are racist."