People can use downvotes however they want due to the freedom of Hive. There are some bullies around, but most people never downvote. I'm not sure they are as big of an issue as some make out, but those affected will feel hard done by.
I don't delegate to big curation projects for various reasons. I think they wield too much power, but when it comes to downvotes then they may be a better source to reduce reprisals against individuals.