I also find these comparisons terrible, but I don't judge people anymore, it's easier for them to associate how big one artist is in their country, if their career is more about image, singing, dancing, or even being controversial or not... If they grow interested of the artist they will eventually grow out of this comparison
I saw an article once comparing Kuu to Xtina, and if you take it deep it's dumb cause Xtina came out of a TV program and started very young and popular, while Kuu came from auditions and gained success later... But the comparison, I guess, is towards the changes on pop, sexy and romantic styles/images that other singers don't usually do. Hot Stuff and Dirrty are pretty comparable imo, so are show girl and Ain't No Other Man and so on...