There will always be certain standards as to what qualifies as a certain kind of music. You wouldn't look at, for example, Nine Inch Nails and call it country, would you? To be properly called a country artist (or indeed an artist for ANY form of music) requires certain standards as to what qualifies as that form.
In Taylor Swift's case, for example, WHY call her a country singer? What is it about her music that ever sounded like country? What qualifies her, now or in the past, to be able to lay claim to being a country artist? Think about it.
Sorry for mentioning Charley Pride (didn't know there were so many haters) but let's consider, for example, Dire Straits. I might argue that their last album (On Every Street) qualifies them as a country act, since not only does it have a steel guitarist as a permanent member of the band, but also Vince Gill sings backup on it - hell, he was even invited to join permanently as well!