Well, everyone's entitled to their own opinion I guess. Though admittedly, it is nice to have a tame forum around.
No need for the holy hammer. I was just curious, since it isn't a rule I've come across on any other forums. It's not like I've been here since the beginning or keep an eye on every single post, but if it has been a problem and a rule needs to be enforced, then so be it.
Strange that you have never come across the rule before, I think a lot of it has to do with slander and protecting the admin/owners of a website. If a member of a forum comes along and posts negatively about a person/company and those allegations turn out to be false, then that person/company are able to sue the website for defamation of character... at least its something along those lines, which is why the rules are there to essentially protect the forum.