I am not sure I understand why those who downvote are invisible to everyone else. It is not that it is some sort of secret or. If done responsibly and explained why there is nothing wrong with voting down an answer.
But it has repeatedly happened that a specific user is down-voting numerous answers of mine for no apparent reason other than taking things personally as a result of earlier disagreement or what have you (I am not clear why someone would do that). I behold this website as adding value to myself and also to the knowledge of others. But granting safe passage to certain disturbed individuals who have no other intention than stirring up dissent and frustration by mass-down-voting makes me wonder why they are protected and there is nothing that can be done against them.
Is there a way for a moderator to look into this. Having 4 or 5 answers down-voted in a matter of a single or two days just does not sound right.
Those who are not professionally or academically connected to quant finance are encouraged (and sometimes forced) to look for answers elsewhere and I would expect the same rigor should be applied to individuals whose clear intention it is to grind an ax they have with someone they have an issue with for the sake of keeping up the high quality of this site.