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.
If you want privacy on the fediverse, use an alias. It’s as easy as that. This is akin to the old adage “don’t tell your real name on the internet” which Facebook destroyed.
An alias isn’t instant privacy. If you upvote your local sports team, downvote a local politician, etc and never comment anti-establishment sentiments that still builds a profile which could interest someone who has no need to have access to that information.