The point of the course is to nudge drivers towards better behaviour. If they are arguing, then they are resisting behaving better, and so points and a fine should be the result.
Thinking that there needs to be some oversight of this, kind of like the secret shopper principal. On my course I am sure the instructor started with a piece about "it's never your fault - YES IT IS". We had a varied mix of people on my course, including someone who ran her own "self worth / improvement" business who came across as very much having her own opinion (dress, name, website), but she contributed positively to the session.
(ran a red light - only just turned from amber, was late, and I thought I would take the risk)