silent the views you disagree with by making them unreadable and it's rather trivial to set up for folks here
this stopped happening immediately after I created new account, if HN would be transparent and showing who flagged or downvoted your comment and everyone would need to provide publicly visible reason for doing it we wouldn't have this discussion
What's the motivation behind such thing? Why bother setting up bots for downvoting accounts?
(FWIW I often get upvoted within seconds of posting)