So from my understanding, I can block an instance which prevents it from showing in my feed.
However, if the instance I post to (.world) is not blocked on the receiving instance’s end (Meta), they will still get my post (unless defederated)?
If so, doesn’t that open up the idea that Meta will be able to scrape and take ALL the data from ALL the (still federated) instances’ posts that are not blocked by the Meta instance(s)? How can I protect my information from Meta while still being federated, or is that not possible?
Meta can already scrape everything from every fediverse instance. Hell - if you wanted to and were willing to invest the time and effort, you could scrape everything from every fediverse instance.
By definition, everything that you post online is accessible to other people. The devices through which those other people view the content you posted are able to make copies of whatever they view. So literally anyone with a computer and an internet connection can already “take” whatever you post.
There’s only one way in all the world to protect your information, and that’s to not post it in the first place. The instant you post it, anyone who cares enough to do it can “take” it, and there’s NOTHING you can do to stop them.
If Meta cares about your information, they’ll go ahead and collect it anyway, with or without Threads or federation with Threads.