That information is already public knowledge (aside from your IP address, I assume the Threads policy is actually talking about the instance’s IP address). I can collect all of that info about you right now myself, without even running my own instance, because kbin exposes that data. Every other instance that your posts touch gets that info too.

If the Threads instance was defederated, sure, they wouldn’t see it through that particular view. But they could be quietly running any number of other instances out there already just for the purpose of harvesting that info. Or they could be using a webcrawler or an API to get the info from some other third-party instance.

I think ultimately people need to accept that when they post something publicly - posts, comments, profiles, etc - then by the very nature of it being “public” everyone can see it. You can’t simultaneously “protect” and “publish” this information at the same time. It’s the DRM paradox, but even harder to resolve than the usual. The only way you can “protect” this information is to not publish it in the first place - ie, don’t have a profile on the Fediverse and don’t post comments on it. Because the Fediverse is designed to spread that information around.