By the way, I'm seeing another type of downvote account lately. Example: @fuk.themarkymark

Instead of attacking the entire platform with hundreds of tiny accounts, this is a single account, dedicated to attacking a single target.

This account DOES make posts and comments, so its targets will be able to retaliate (and already are). That means it will lose rep, and its comments will be harder to see, and it probably won't grow on its own. But it already has someone delegating 25 SP, and that could rise. Those SP can't be removed by downvoting, so in theory, downvote accounts like this can and will have a lasting effect.

I think I'll nickname this type of account "the tick". It latches on to a victim and drains it slowly.