Maybe that's nobody, maybe I'm paranoid, maybe I'm not following HN guidelines. IDK.
It is also noticeable that downvotes often come in clusters where a given post suddenly gets downvoted several times within a short time frame where there otherwise has not been any activity around that post. Whether this is caused by a bunch of ideologically-aligned users having some downtime - Compiling - or something more nefarious like sock-puppet accounts being used as ideology amplifiers is not clear and can only be investigated by Dang et al.
The up/downvoting system is one of the less successful aspects of HN, especially where it concerns downvotes. A meta-moderation system like the one used by Slashdot of old could be of help here but I suspect the site owners prefer the simplicity of the current system over one which, while more 'fair' does have the tendency to keep growing with the meta-moderators being moderated by meta-meta-moderators until it is moderators all the way down.