I think the installation of the new group software will help with a lot of this. Participants in a sensitive subject such as the one you linked to would be able to move their discussion to a group unit where they can administer or not administer their own standards of moderation for their more sensitive posts and use the main A2K forum (we need a shortcut reference name for this) for the "my sources and statistics are better than yours" ping pong match.
Until we have the group software and can see it in action, I'll reserve judgment over whether people should be banned from the main A2K for their untoward opinions.
If the group software were to never materialize, I don't think untoward opinions should be banned, but I do think improved mechanics are needed now that some voids in the safety-net of our thumbs up/down system have been exposed.
What comes into play is the contention between self-moderation and site-moderation. For self-moderation, it is easy to use the ignore user button and the problem is solved for ourselves but does nothing to aid in the site-moderation goals of having the thumbing system cause posts to be automatically collapsed when they fall below a thumbing formula's threshold. For site moderation, using the thumbs up/down on individual posts is time consuming and causes feelings to be affected by those who view the numbers as being important.
Whatever happened to the possibility of just changing the font color of the thumb numbering system to the same as the background color so the numbers are not visible without highlighting them?