Umm is pretty close to the mark actually.
The News section is about conflict, so there is a little more leniency - you can't talk about politics without an argument (also see: religion).
Also, the punch-ups in CB tend to be more personal (rather than "You're a yoghurt knitting communist" "You're a jack-boot polishing fascist" etc).
Often "unsavoury" threads & comments are left alone because more reasonable ABer's tend to make considered and rational arguments - restoring the balance.