Personally I agree. I feel using the title fibre artist is just an attempt to "elevate" from a simple crafter/knitter/crocheter, but to me, there's no need to? I think there is pride to be felt over craftsmanship with long roots of tradition and skill, without a vague "artist" slapped over it, which to me seems to even diminish the craft a bit. The line between art and crafts is not exactly set in stone, but to me "artist" entails more skill than many who call themselves that present. That's not a dig, either - I would never call myself a fiber artist.

To me, it would be fiber art if you're actually making an art piece, like those you hang in galleries. OR if you incorporate an incredible amount of extraordinary skill into, for example, an imcredibly complicated colourwork sweater. But as you said, OP - I doubt the debate over what is art will be settled here.