It's actually even worse on some sites. For example Reddit does not necessarily show the real sum of votes to begin with, but a different one created in an intransparent manner since the code isn't public. They call this "vote-fuzzing". Arbitrary changes to the ranking algorithm have over the years completely changed what users see when they look at the vote count¹, and I suspect that's just the tip of the iceberg that's made public.
Right, this is sold as a technique against vote manipulators (to not let them know if their bots are working) but it requires a lot of trust in the operator not abusing it.
¹https://old.reddit.com/r/announcements/comments/28hjga/reddi...