I recently learned that voting on lemmy is not anonymous. Anyone can get information about who has upvoted and downvoted a post or comment.
In combination with your IP, this is a massive privacy (maybe even physical security) risk. Also, people can target you for your votes.
Sadly, this is something where I would prefer Reddit over Lemmy. Big tech scrapes data from both places anyways, at least Reddit is safe.
Voting is only seldom private IRL, only in very specific situations like in very important national elections.
When you vote for what to get for lunch together or for who will be the head of your local football club or who will be the speaker in your school, most of them are public, similarly to Lemmy votes.