Ask HN: Why does Spotify not let users disconnect from Facebook?

I have an old account that was created using facebook. Unfortunately, Spotify's answer for disconnecting FB from my account is to just create a new account and cancel the old one?!?

https://support.spotify.com/us/account_payment_help/account_help/i-want-to-use-spotify-without-facebook/?ref=in_top

Doesn't this seem ridiculous? They have my email as the username, why not just set a password on the account and disconnect from FB?

This just smells like it was designed on purpose, as they don't want you to disconnect from FB.