Eh, that's not really true. The concept of "privacy" has been broadly corrupted by centralized services. There is no "privacy" when you provide information to another person, let alone publish it to the world. Never has been. You never had any actual "privacy" on any platform. What you had was admins lightly concealing from you the manner in which they used the information you provided. That's not "privacy".
Actual privacy only comes when you shut your mouth and keep a thought to yourself. As soon as you put the idea out, you abandoned your expectation of privacy.
The purpose of Lemmy is communication. It is designed to share the information you provide to the general public, whether that information is a post, a comment, an upvote or downvote. It is designed to limit and bypass attempts at centralized control over the flow of that information.