This is what everyone said they wanted after Cambridge Analytica! For platforms to exercise due diligence before allowing users to delegate their access to third parties.
To be clear, the problem with Cambridge Analytica was not Cambridge Analytica. The problem was - and still is - Facebook's habit of getting everyone to overshare and self-surveil. There needs to be some control and vetting over the apps that have access to your data but not so much that actually honest developers are quitting the game.
My guess is that Google just doesn't want third-party clients (you can't shove "AI" or "Investor Advertising" into it), so they're slowly turning up the heat by abusing the data scare.
My Facebook account is largely limited to information that’s already largely public. I imagine there are Google Drive accounts out there with tax returns, health records, background checks, etc in them.
Yes, this sucks that it puts road blocks for well meaning developers, but for the general public, it’s pretty hard to tell who is a well meaning developer and who isn’t. Also, inexperienced or careless well meaning developers can still accidentally put your data in a public internet facing DB.
Nowerdays this seems like an incredibly dumb idea, sure, and personally I disabled it entirely the moment it came out. But we can cut them some slack, because back in ~2006 facebook was a new thing, for young people - and nobody was sure where this new "social media" thing was going to go.
On top of that I believe Cambridge Analytica did the usual "personality test" trickery where you fill out a survey, then it won't show your result until you hand over your details and accept some legal mumbo-jumbo.
So your Great Uncle wanted to know what harry potter character he was, clicked a consent button, and Cambridge Analytica got your PII.
Facebook provided a general API for apps, not some kind of data feed. The API required user consent from the app user, though almost certainly not informed consent.
The API also provided too much data, in particular on the user's social graph, which is why a single user giving uninformed consent would lead to data being extracted for multiple others. But even if the app had informed users about intending to steal the social graph, most users would still have consented. They would not have read the text, or not cared. Just click ok until the computer lets you do what you wanted.
So we really do know that the only way to safeguard the data is to design safe scoped APIs for the typical use cases, and keep dangerous unscoped APIs around only as an escape hatch with much stricter security and safety requirements.
These are illegal otherwise, but very useful for journalists reporting on political matters.