In theory this could work on Lemmy as well but since you're on kbin I would definitely recommend utilizing kbin's activity feature which lets you view these downvotes (kbin calls them reduces) and who made them. You should check other people's posts on their profile and see if the same people have been mass downvoting for seemingly no reason. Then you can start blocking these people.
As for the idea of making down votes from the profile page not count, that doesn't really seem like a good idea considering that kbin allows posts exclusively from your profile (and Lemmy might add the same in the future) it would essentially make those posts unable to be voted essentially stifling all profile posts' growth.