The downvotes can be very toxic and bad in the wrong hands and used for the wrong reasons, that's why there's only 25% mana to them so people can counter those being used wrongly. The bad actors will quickly stop using downvotes once it starts eating at their upvote mana (potential curation rewards) and if there's a lot of countering and backlash from upvoters disagreeing with the downvotes even if it means they get less curation returns from countering. In this case here it seems well deserved if someone for years has been tricking people into voting up a secret alt instead of disclosing it was his to begin with.