what you describe is called "shadow banning".

https://en.wikipedia.org/wiki/Shadow_banning

That's not the important part. My point is that moderators should be able to see or at least set policies on what people vote... if these 3 posts are good and fit with the community, maybe someone is still permitted to downvote 1 of them. Just personal preference after all. But if they're downvoting those (and all the other good fits), then they're simply not compatible with the community. So a "people who constantly downvote good fits" (or upvote bad fits) are punished/removed/whatever.