the same people who say songwriting/playing an instrument are required mention Britney. but Britney plays the piano and has a lot of songwriting credits. she even wrote for other artists like bjork and selena gomez
music is art, so i don't see how any pop girl couldn't be considered an artist
This is my feeling as well. Of course some have less artistic input than others but unless they have absolutely no artistic input whatsoever (neither composing nor vocalizing) I'd consider them artists.