There can be contentious topics. However, the management - here, CGL - have made it clear that this forum is meant to serve as a friendly community, not an intellectual bear-pit.
As such, if forum members can't stay within the rules when discussing a contentious topic, the forum management will act to keep the forums friendly. After all, we aren't moderating a topic - we're moderating the actions of posters who can't stay inside forum rules when discussing a particular topic.
I trust no-one's claiming a Ghu-given right to use these forums as a place to unleash their aggression. Other forums make their own rules, and we'll respect that. But that doesn't mean we'll not follow our own rules.
After all, think of all the arguments that typically don't have at big family gatherings. Unless there's always someone who wants to talk about ice hockey, and everyone else groans inside because they know just where this is going.