I think the issue centers around the difference between public and private.
If I invite a number of friends to the park to talk about something or other and an uninvited person wanders over into our group I'm going to have a hard time finding someone to remove them from the park. On the other hand, if I invite my friends to my house I certainly have the right to remove those I don't want.
In my mind these boards are like public parks. Everyone has a right to be there within certain boundaries. The creation of private boards would be allow private groups.
If you did create them I think they should in fact be private. Only those with permission for the group should have access to the posts. That way nobody gets up in arms over stuff they don't agree with.
IHub Moderator Ethics - It's not an oxymoron. #board-2807