Accounts "The_Lion" and "The_Lion2" are banned now. Here is some background, mostly for the users who weren't here two years ago:
User "Eugine_Nier" was banned for retributive downvoting in July 2014. He keeps returning to the website using new accounts, such as "Azathoth123", "Voiceofra", "The_Lion", and he keeps repeating the behavior that got him banned originally.
The original ban was permanent. It will be enforced on all future known accounts of Eugine. (At random moments, because moderators sometimes feel too tired to play whack-a-mole.) This decision is not open to discussion.
Please note that the moderators of LW are the opposite of trigger-happy. Not counting spam, there is on average less than one account per year banned. I am writing this explicitly, to avoid possible misunderstanding among the new users. Just because you have read about someone being banned, it doesn't mean that you are now at risk.
Most of the time, LW discourse is regulated by the community voting on articles and comments. Stupid or offensive comments get downvoted; you lose some karma, then everyone moves on. In rare cases, moderators may remove specific content that goes against the rules. The account ban is only used in the extreme cases (plus for obvious spam accounts). Specifically, on LW people don't get banned for merely not understanding something or disagreeing with someone.
What does "retributive downvoting" mean? Imagine that in a discussion you write a comment that someone disagrees with. Then in a few hours you will find that your karma has dropped by hundreds of points, because someone went through your entire comment history and downvoted all comments you ever wrote on LW; most of them completely unrelated to the debate that "triggered" the downvoter.
Such behavior is damaging to the debate and the community. Unlike downvoting a specific comment, this kind of mass downvoting isn't used to correct a faux pas, but to drive a person away from the website. It has especially strong impact on new users, who don't know what is going on, so they may mistake it for a reaction of the whole community. But even in experienced users it creates an "ugh field" around certain topics known to invoke the reaction. Thus a single user has achieved disproportional control over the content and the user base of the website. This is not desired, and will be punished by the site owners and the moderators.
To avoid rules lawyering, there is no exact definition of how much downvoting breaks the rules. The rule of thumb is that you should upvote or downvote each comment based on the value of that specific comment. You shouldn't vote on the comments regardless of their content merely because they were written by a specific user.