This is a strange line of thought . I think some of the measures already put in place to curtail these excesses are the "report to moderator" button and the trust system, which includes positive, neutral, and negative ratings. Another measure on an individual level is to write to them directly. However, a demotion or demerit button is not an effective way to deal with it. Instead, you can use the ignore button for those specific users if their comments bother you so much. One other thing you could do is whenever you create a topic, you could self-moderate it by deleting comments that aren't useful or helpful to the conversation, thus keeping it clean and maintaining a meaningful discussion.