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.
Anonymity is not the reason why many platforms have turned into "dumpster fires". Have you checked Facebook lately? People literally use their real names while lighting the whole dumpster on fire.
No, privacy is more important now than ever. If I had to list all the ways our data is being used against us nowadays, I would exceed the character allowance on here. The short version is that historically, time periods were named after the materials civilization made their weapons out of (stone age, bronze age, etc.). That's the reason why the current time period is called the Information Age. Data/information is the biggest weapon we have nowadays, and that's why it's critical that we protect it with all means possible if we want to retain our freedom.