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.
How specifically? What would votes be tied to in such a solution? Could you share a reference or explain more? Btw, there’s nothing preventing any federated instance from vote flooding (with or without anonymization, since it’s not associated with any cost) is there?
One example (not the only way to deal with this) is to do what some crypto algorithms have done. Here’s the source code for z cash: https://github.com/zcash/zcash
Using something similar to this you can hide who is voting for what while being able to trust that the number of votes are accurate.