They must have, i'm a Spotify sub and i've never used FB with Spotify. At least, that i remember. I rarely (read: maybe once a year) login to FB so i despise any FB-only login services.
How opposed would you be to creating a shell fb account with zero personal info and a fake name, in order to log in to products? I realize you shouldn't have to take this extra step, but so many wonderful products DO require an fb login...