I know she started off as a Country artist, but can:

That don't impress me much
Man, I feel like a woman
I'm gonna getcha good
& other more recent tracks by her

be considered Country, just by virtue of who performs them?

She stopped being country when she met ( and married ) Mutt Lange. he produces and writes some of her stuff now

It seems that a track's 'genre' is getting dictated by the normal output for that particular artist, which in my opinion is complete rubbish.

I think the track should be judged alone, and not in relation to the artist's past tracks.

Those Twain tracks you listed are most certainly not country.

But given this media-driven labelling, how come Steps weren't instantly labelled as 'country', after their first hit '5,6,7,8'?

My thoughts exactly, I just wanted reassurance that I wasn't alone

those tracks were remixed for the UK market and can be found in there original country version on her cds in the good old US of A..

well thats what the sticker on the CD album said

It's contemporary country, isn't it?

I can't comment on how things should be (generally), I can only say that an artist like Madness, who are an out & out pop band, are archived under ska/two-tone on my laptop, not because they are a ska outfit, but simply because that is how I remember their first couple of efforts, and it is therefore easier to archive the output from any particular artist in one folder, rather than several.
As regards Shania, her worldwide popularity stems (at least musically) from the pop genre, even tho' 'gonna getcha...' (was that the album title?) was released in two formats: 'rock'(!) and country. At least in Europe where I bought it!

I don't really care whether she's country, pop or whatever, as long as people continue to dance to her. Why does everything have to go in a nice tidy little pigeon hole

I have an album entitled "Country Meets Soul" containing tracks by Al Green, Brenton Wood, O.V. Wright, Charlie Rich, Otis Clay, Willie Clayton, Ann Peebles and Narvel Felts.

As the title suggests the Soul artistes perform Country songs and vice versa.

One of the Charlie Rich tracks is the Hayes/Porter song "When Something Is Wrong With My Baby".

Is it Country, Soul, Country Soul or Soulful Country?

The reason I ask is I'm compiling genre lists of track that work for specific genres & all of the tracks I mentioned have been sugested. Thing is I don't consider any of them to be Country

Shania Twain still features in US Country charts under the "Modern Country" sections.

Country music is divided into several seperate areas, such as Country Rock, modern, cajun, bluegrass, hill-billy and alternative as well as the more traditional style.

Listen to some newer artists and you will find that a lot are very "pop" orientated but still classed as country. It is no longer all Willie Nelson and Johnny Cash, who incidently wrote and recorded a number of tracks which are not strictly country. In fact the song that is probably most sung and recorded by other singers must be one that very few even realise he wrote .... Forty Shades Of Green which is thought by many to be Irish.