Ah, I misunderstood what you were saying at first. You’re right, it’s not everything on the instance that gets sent, only those things that federated instances need.
But as a user, unless I run my own instance, I don’t get to decide when my posts or edits get sent out to any federated servers. That’s what I was referring to. All of that stuff gets sent out “like a firehose.”
And over time, as more people on Threads interact with certain ActivityPub instances, the range of communities Threads will be sent updates for might as well be the entire instance. If I block them, that’s just a visual block. My stuff will still be sent to them, and depending on how they set up their federation, my content might be available on “threads.net” as well.
You can’t have a ton of Pals on your base until you level your base up, but in theory, yes, you can create a gun factory if you work for it.