>> Hence, that's why OP read your post as "try not having ADD", because you're literally suggesting solutions that presume that they not have ADHD in the first place.

To be fair, the article does make the point pretty strongly that it is very hard to separate ADHD from natural variations of attention, concentration etc:

  But “ability to concentrate” is a normally distributed trait, like IQ. We draw a 
  line at some point on the far left of the bell curve and tell the people on the far 
  side that they’ve “got” “the disease” of “ADHD”. This isn’t just me saying this. 
  It’s the neurostructural literature, the the genetics literature, a bunch of other 
  studies, and the the Consensus Conference On ADHD. This doesn’t mean ADHD is “just 
  laziness” or “isn’t biological” – of course it’s biological! Height is biological! 
  But that doesn’t mean the world is divided into two natural categories of “healthy 
  people” and “people who have Height Deficiency Syndrome“. Attention is the same 
  way. Some people really do have poor concentration, they suffer a lot from it, and 
  it’s not their fault. They just don’t form a discrete population.

Also, if attention etc is a "normally distributed trait", any behavioural intervention that can help someone near the middle of the distribution has a pretty good chance of helping someone near the extremes, also. To take the example of height again, just because someone is short doesn't mean they won't look taller with high heels.

In fact, if you think about it, such interventions are designed exactly to help people with poor executive function, as you say. Assuming that this is basically a description of what ADHD is, I don't see why behavioural interventions can't make a dent in it.