To be honest, I think people enjoyed his style more than his substance.
The core lesswrong community (at least, back when I was more active) don't downvote to disagree. They upvote when something is thought provoking (as contrarian politics tends to be), they upvote novelty (again, contrarian politics) and they are more tolerant of critical tones than other parts of the net.
So even though there wasn't much true insight and most people disagree with most of his opinions, it was interesting enough to read. I know I really enjoyed the influx of reactionaries for the first few months because it was a new and exciting thing...but then it kind of got tiresome - especially when reactionary voices started dominating completely unrelated conversations and influencing votes completely out of proportion to the number of members who actually held those views. Somehow, the reactionary users we had were also among the most active users, and naturally, they liked talking about politics.
(Please note: While I did not explicitly say it, the above implies by connotation that Nier and his unethical practices are reflective of reactionaries in general. This is unintentional. What I AM saying is that the reason Neir was upvoted is the same reason that reactionaries were upvoted, and the things I disliked about Nier's writings is the same thing that I dislike about many but certainly not all of the reactionary user's writings - in short, compelling style and novelty but failure to use parsimony and substance, too much confidence in opinions reached via long chains of mostly inference - even when they wrote on non-political topics. What I'm NOT saying is that all reactionary users are behaving unethically in the manner of Neir.)
As previously discussed, on June 6th I received a message from jackk, a Trike Admin. He reported that the user Jiro had asked Trike to carry out an investigation to the retributive downvoting that Jiro had been subjected to. The investigation revealed that the user Eugine_Nier had downvoted over half of Jiro's comments, amounting to hundreds of downvotes.
I asked the community's guidance on dealing with the issue, and while the matter was being discussed, I also reviewed previous discussions about mass downvoting and looked for other people who mentioned being the victims of it. I asked Jack to compile reports on several other users who mentioned having been mass-downvoted, and it turned out that Eugine was also overwhelmingly the biggest downvoter of users David_Gerard, daenarys, falenas108, ialdabaoth, shminux, and Tenoke. As this discussion was going on, it turned out that user Ander had also been targeted by Eugine.
I sent two messages to Eugine, requesting an explanation. I received a response today. Eugine admitted his guilt, expressing the opinion that LW's karma system was failing to carry out its purpose of keeping out weak material and that he was engaged in a "weeding" of users who he did not think displayed sufficient rationality.
Needless to say, it is not the place of individual users to unilaterally decide that someone else should be "weeded" out of the community. The Less Wrong content deletion policy contains this clause:
Although the wording does not explicitly mention downvoting, harassment by downvoting is still harassment. Several users have indicated that they have experienced considerable emotional anguish from the harassment, and have in some cases been discouraged from using Less Wrong at all. This is not a desirable state of affairs, to say the least.
I was originally given my moderator powers on a rather ad-hoc basis, with someone awarding mod privileges to the ten users with the highest karma at the time. The original purpose for that appointment was just to delete spam. Nonetheless, since retributive downvoting has been a clear problem for the community, I asked the community for guidance on dealing with the issue. The rough consensus of the responses seemed to authorize me to deal with the problem as I deemed appropriate.
The fact that Eugine remained quiet about his guilt until directly confronted with the evidence, despite several public discussions of the issue, is indicative of him realizing that he was breaking prevailing social norms. Eugine's actions have worsened the atmosphere of this site, and that atmosphere will remain troubled for as long as he is allowed to remain here.
Therefore, I now announce that Eugine_Nier is permanently banned from posting on LessWrong. This decision is final and will not be changed in response to possible follow-up objections.
Unfortunately, it looks like while a ban prevents posting, it does not actually block a user from casting votes. I have asked jackk to look into the matter and find a way to actually stop the downvoting. Jack indicated earlier on that it would be technically straightforward to apply a negative karma modifier to Eugine's account, and wiping out Eugine's karma balance would prevent him from casting future downvotes. Whatever the easiest solution is, it will be applied as soon as possible.
EDIT 24 July 2014: Banned users are now prohibited from voting.