Conspiracy theories are very enticing to the human mind, so they often get too many upvotes here on HN. Although I did downvote pg's first comment in the thread mentioned here, I was outnumbered by many more people who upvoted it, mistakenly.
Top comments in a thread frame discussion - if the top comment in a thread is a conspiracy theory, then it's likely that the entire discussion will be derailed. For that reason, I think it's valid to downvote such comments, to prevent them from derailing the discussion.
Comments
Case in point: has PG ever been downvoted? Ever?
I downvoted a recent comment by pg that for quite a while was (and STILL is) the top comment in its thread
http://news.ycombinator.com/item?id=4253156
but that pg later acknowledged didn't have a sufficient factual basis.
http://news.ycombinator.com/item?id=4254592
Conspiracy theories are very enticing to the human mind, so they often get too many upvotes here on HN. Although I did downvote pg's first comment in the thread mentioned here, I was outnumbered by many more people who upvoted it, mistakenly.
It is perhaps more useful when a mistake is corrected with a reply/comment, than with a down-vote.
Doing so gets people to read both. Besides in the absence of the original comment (incorrect as it may be), the followups lose context.
Reserve down votes for opinions that do not deserve a reply. Such as pure trolling.
Top comments in a thread frame discussion - if the top comment in a thread is a conspiracy theory, then it's likely that the entire discussion will be derailed. For that reason, I think it's valid to downvote such comments, to prevent them from derailing the discussion.