French people have got a funny relationship with their language. They give t almost a godlike status. There are laws regulating it. If you make a slight mistake people will usually let you know, which can be very discouraging for learners. Yet, the latest reality TV show has got an English title: the Voice. Why didn’t they choose: “la voix”?
My guess would be a branding thing – it’s an american show, it’s on in the UK at the moment as well. What I did find strange when I bothered watching it (i.e. until a colleague of mine got voted off) was how French people were worried about singing in French for the first time because they’re so used to singing English songs…
I think you are probably right about the branding thing, and “ze voïce” sounds much better than “La voix”.