I am unable to open your link where I am right now so I cannot read the article about French kids.
I grew up in a time where ADHD was real, but was not labeled and for the few doctors who did know that it was a "thing," medications were yet to be prescribed. My DH had it (and still does as an adult but is in a profession that works well with it), he was NEVER a behavior problem, nor were his non-ADHD siblings. Parenting was not a factor. He could NOT stop moving, and still cannot. He was "treated" with coffee and being tied up in a chair. Today he has a very physical job, he's one of the most reliable employees in his company, and he has completed several triathalons and popular marathons. He is in his 50s.
My next door neighbor (one of three children) also had it and had awful times in school (never treated). Not sure whatever happened to him but looking back, I feel so bad that he had to live through it without some help.
One of my employees (a 64 year old man) was diagnosed with ADHD when he was in his 40s and his son was being diagnosed. Again, never a behavior problem that was due to a parenting "role" but immense anguish in the classroom.
What do I think? The U.S. system of education is cookie cutter and not conducive to people who learn physically (or kinetically). I think other school systems may do better with different types of learners. I do not believe that ADHD is a true disorder. I think it is a variant of "normal" and it is a different way the brain works. Evolutionary-wise, it was probably very advantageous for something and, if an ADHD person can make it through the "jail" of school (for them), they are often brilliant, creative people to have in your employ.
Wonderfully stated.