You have worked helping people edit essays in over 30 different countries? And only Americans address their theses in their writing? If you saw an essay titled “Why dogs are better than cats” you would only expect an American to mention cats? That sounds insane, downright reductive and infantilizing.
I apologize but I am getting a little bit of secondhand embarrassment from seeing someone look at objectively bad writing and saying “This is actually an example of the famously uniform culture of France and Spain” ???
As an aside, where did you develop the “cross-cultural skill” of haughty dismissiveness out-of-hand in response to gentle disagreement?