I don't know exactly what to think. It is a kind of safeguard, say, to prevent spam and plagiarism, but lately, I have been following it and it seems that some people are using it for personal reckoning, which is not good at all. I never use downvotes.
I think that when a case like this comes up (like Marc-Allaria, the photographer who was accused of posting a photo somewhere other than Hive, or this last one with Uwelang where the personal fights moved from the discord to the downvotes) it needs to be changed somehow.
I think that in such cases there should be a body, made up of let's say prominent Hive members (and I don't mean whales), that would be above the Hivewatchers and then adjudicate whether the downvotes are justified or not.
But that is just my opinion.