However, in a following paragraph WP:OR states: Wikipedia:No original research (NOR) is one of three content policies. The others are Wikipedia:Neutral point of view (NPOV) and Wikipedia:Verifiability (V). Jointly, these policies determine the type and quality of material that is acceptable in articles.

As you can see, I'm right in using original research in the discussion page, because NOR applies only to the material included in the articles. The discussions do not form part of the Wikipedia contents, even if Wikipedia users have full access to them.

By the way, my contention that Muir's article is not scholarly is based on the HNN's FAQs, which declare the journal not to be scholarly. Therefore, it's not original research.