Unless we talking polls, normally they should be public. It encourages accountability, discourages the place becoming a shit hole like the YouTube comments section, and moreover is just plain more friendly to federated instances than to have these flood of oddly named accounts.

Conversely, making votes private would encourage rather than discourage voting manipulation tactics, by obfuscating normal voting patterns, within which manipulation could be hidden among.

Please also keep in mind that nothing on the internet is truly private. iirc, someone can always gather your identity by e.g. sending out an image on a self-hosted server and then watch the IP addresses of the recipients that download it, or YouTube will show demographics (gender, approximate age range, etc.) of people who click to watch a video there, which if few enough people click within a given timeframe can be used to help identify people.

I don’t mind that someone knows that “OpenStars has up/downvoted this content” - it is part of living in a society where one’s contributions are observed in the context of the larger world. I normally even take the time to respond if I ever downvote, unless I’m merely adding mine to a pile of existing ones. And given this context, I don’t really see the appeal of trying to obfuscate that? Besides, if I truly wanted to do so then I could always create an alt (or hundred) and accomplish an anonymous downvote, without the need for it built into the system? I don’t really see the use case for private voting I suppose.