You got your answer through the fact that your report wasn't handled by the admins and the thread is still there with all the posts. The best approach is to find things like multi-posting, off-topic replies, or low quality posts and report those. That stuff is against the rules and will be deleted by mods if reported. I am not sure if there is a rule about creating fake conversations by the same group for the sole purpose of bumping threads. But if not, that should be added. If an entire thread page is covered with posts of the same group of users and that same group dominates the entire thread with unnecessary comments, admins should react to it.