Its not vote manipulation as such here. Its much simpler than that. Lemmy has a spam problem. People coming in to just make shill communities selling a service or product or spamming advert posts across communities.

They usually get downvoted, but I can use Piefeds admin tools to filter for downvoted posts by new accounts. This usually catches most spammers like that. I can then ban them from piefed.social and pass that on to Lemmy admins.

A lot of Day 1 trolls are caught like this too.