I agree with your reply. That’s the same thing that ran through my mind when reading this article, respectfully speaking. I don’t think single words and phrases become red flags. Otherwise, I’ll have to spend more time using thesauruses looking for synonyms of “furthermore”, which sounds more “me” than using thesauruses more pretentious(?)-sounding words “thus” or “hence”, which surprising,y weren’t on the author’s list.
I believe that it’s more about the construction, consistency, and coherency, rather than lexical markers. Imho.