The best part of the fediverse is that anyone can run their own server. The downside of this is that anyone can easily create hordes of fake accounts, as I will now demonstrate.
Fighting fake accounts is hard and most implementations do not currently have an effective way of filtering out fake accounts. I’m sure that the developers will step in if this becomes a bigger problem. Until then, remember that votes are just a number.
Reddit had ways to automatically catch people trying to manipulate votes though, at least the obvious ones. A friend of mine posted a reddit link for everyone to upvote on our group and got temporarily suspended for vote manipulation like an hour later. I don’t know if something like that can be implemented in the Fediverse but some people on github suggested a way for instances to share to other instances how trusted/distrusted a user or instance is.