I believe there should be a way to block people that are following you on Spotify. When blocked, the user will automatically unfollow you and will not be able to find you, or view your public playlists.
Blocking should be possible via both username and email address.
We definitely think this is a strong idea, however it isn't in our current road map. The teams behind our social features are aware that you're bringing your feedback here and we're working closely with them to bring forward all your comments and concerns.
If there are any updates on blocking Spotify followers we will let you know here first.