Banning someone from the list server is fairly serious. It should only be done when the perpetrator does something deliberately to damage the integrity\stability of the list server (i.e. denial of service attacks or extraneous fake servers), or more generally to negatively affect other users accessing the server. It should not be done on the basis of emotion or opinion.

For example, if Darker were to host servers with names offending Nimrod, that would not be a suitable reason for banning. However, if Darker were to list multiple fake servers, regardless of their name, it would be a suitable reason for banning.

I don't know any details of what happened here, so this post is for both Darker and Nimrod. One should also note that since Nimrod hosts the server, he has every right to do whatever he wants because he's the one hosting it, and not on the behalf of someone else. However, he would not be a good list operator if he bans people without adequate reason.