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.
I don’t agree that there’s been no pushback with regards to Facebook. Plenty of privacy advocates dissuade people from using it at all.
The lack of anonymity with regards to the upvote/downvote thing is just one example of things that might not be obvious to the typical user. Another would be consideration for people who moved away from Reddit so they would “stop slurping up my data”. Thing is, the way the Fediverse works, pretty much anybody in the world can slurp up a much of the same data.