Unmoderated boards are kind of a paradox because if you let total retards or deliberate malicious actors flood nonsense out, effectively censoring other people trying to participate more genuinely. It's called a "Heckler's Veto", and it's especially bad on anonymous boards without thread ids.
Like on one hand you really do want people to be able to post as quickly and as freely as you want, but on the other hand that kind of behavior drives people away. A site like 4chan is popular because it's popular. There's lots of little IBs they are basically stillborn, despite some being good ideas, because unpopular things remain unpopular.