there is another issue with the Kielhorn quotation, I would say, namely that most (or at least much) of the inserted material is not necessary at all!
"All of this is inadmissible" is EXACTLY the same thing as "All of this is, however, inadmissible", with or without parentheses.
Every individual word? Is that somehow different from every word?
So I'm not entirely sure in this case also why Dominik picked this example, although knowing him I would not be surprised if he had this very point in mind as well... (and yes, I did not notice the incoherent sentences later in the paragraph...)