Edit: obligatory explanation (thanks mods for squaring me away)…
What you see via the UI isn’t “all that exists”. Unlike Reddit, where everything is a black box, there are a lot more eyeballs who can see “under the hood”. Any instance admin, proper or rogue, gets a ton of information that users won’t normally see. The attached example demonstrates that while users will only see upvote/downvote tallies, admins can see who actually performed those actions.
Edit: To clarify, not just YOUR instance admin gets this info. This is ANY instance admin across the Fediverse.
The admin of the Mastodon instance I use has a very well thought-out process anticipating how to deal with this alleged, possible federation of FB’s “threads.net”. It will be allowed, but tools at hand to deal with, and hold them to following AP rules, required openness, sharing etc. Exceedingly wary, prepared, but open to possibility. I think that’s the right approach. We’ll see won’t we…!