Spotify support staff quote from that discussion thread

-- Hey Guys thanks for your question, Unfortunately you will need a Facebook account to access Spotify from now on, unless you already have an account set up.

This does not stop you creating the Facebook account adding nothing to it and making it totally private as the Facebook account does not have to be actively used. --

Couple of things to note:

1. If you already have a Spotify account, you don't have to connect to Facebook.

2. They seem to be encouraging a bogus Facebook account as a way to use Spotify "privately"?