It is only shocking if the expectation was set that your votes are private. If you wanted to avoid linking an identifiable account with their votes then you could use a de-identified user account to track a user’s votes.

You could to perform deterministic hashing prior to persisting a vote to ensure that those looking at the database can’t go backwards to find the specific users who voted on a post. But any service that knows the salt and hashing algorithm can start with a user account and determine that user’s voting history.

This allows you to track up/down votes per user without allowing over-priviledged DBAs or malicious actors from poking around voting histories of identifiable users.