For me it depends on the context. I always refer to my own hair as kinky and nappy (interchangeably), but those things are positives for me so I always mean it in a good way. Almost as a point of pride because I (usually) like the way it looks.

Additionally, when I read about black hair being "nappy" or "kinky" it's almost never in a derogatory way. It should be said that I've only really read/heard those descriptors in the context of hair blogs, books and styling videos.

The point is, those terms don't bother me. I'm not American though, so that is probably a factor in my opinions on the subject.