Federation basically just means your instance will scrape Meta in turn and serve their content to you, whereas being defederated it will not. That means federated or no, without additional precautions by admins of particular instances, Meta will be getting the same info federated or no. Being defederated makes interacting with Meta’s service much less likely though, which makes them scraping your data less likely. This update to the ToS honestly just sort of describes how the fediverse works anyway this isn’t some special feature of Threads, all instances behave this way.
Yup, or the Apple play which is just walk right around these regulations with some additional tricky bullshit while outwardly ‘supporting’ RtR. If I was a lawmaker I would be so fucking livid about this circumvention I would come back even harder but I guess I don’t know a lot about that process.