If I connect my Facebook to my Spotify so that I can log in with one account and maybe share music with friends, I don't expect Spotify to have access to my private messages.
Obviously context is important, but I'm not seeing the double standard.
What’s more, users explicitly opted in, giving Spotify permission to do so. [1] No reasonable person would use Spotify to send and receive messages after explicitly granting the client permissions and then claim “but I don’t expect Spotify to have access to my private messages”
[1] - https://stackoverflow.com/questions/17561784/django-social-a...
Which they have been shown to about a dozen times over this month.
Or is your claim that you gave only permission for profile and friends but the Spotify client had messaging permission as well?
I disagree. I have perused various trials for Spotify and other services over the years and never once had to resort to using a Federated ID/login.
Of course as a technician with knowledge of how OAuth and web APIs work, the implication that it really needs access to all messages seems a lot more reasonable - but I don't think this view is necessarily valid in a larger context.
Implementing more fine-grained permissions is absolutely possible. See e.g. Telegram: Even though Telegram bots appear as mostly ordinary users, they by default cannot access the messages of the channels they joined - they can only access commands that users were explicitly sending to them. You need a special permission to have a bot actually be able to access a channel like a human user would.
1) if you use their Messenger app plugin
2) if you had connected to Messenger through Spotify's desktop app. I believe this feature has been deprecated for a few years now, though.
Even if you sign up for Spotify using your Facebook account or connect your Facebook account to Spotify that does not give them access to your Messenger messages. It is my understanding that it required the user to opt into specifically connecting Messenger for that circumstance to occur.