A very large difference exists between kids with ADD/ADHD and 'normal' levels of energy in kids, particularly in focus, attention span, conduct and potential for harm (both to others and self).
While this is true you can't deny that to people who aren't aware of the difference they just label any hyper or misbehaving child with ADD, which creates a huge stigma around teh disorder and leads to comments like Wolf's.
One of my daughters best friends has a brother with ADD/ADHD, he gets so uncontrollable that when out shopping they have no choice but to use a buggy for him (he is seven), as you can guess this can get quite funny looks. He is a lovely lad, but his violent outbursts are both frightening, destructive and a long way from the norm.
Please tell me they have exhausted the multiple different medications available before strapping the kid to a buggy so they can go out. If they have exhausted the medication routes they may want to see if he doesn't have other factors other than just AD(H)D.
The kids themselves and their families want and need help and understanding, not derision and a refusal to believe. I have to say I find comments of dismissal like this to be on par with telling people with eating disorders to stop whining and have a good meal, its neither the right thing to do and far from being constructive, its potentially very harmful.
The best way to prevent these kinds of comments is to work more at being able to accurately diagnose ADD/ADHD. This way parents with poor parenting skills can't use the disorder as an excuse and apply even more stigma to the disorder. Your daughter's friends seem to be doing everything possible to control their child, but many parents are busy working all hours of the night, going out on dates, being kids themselves, or just being bad parents and their kids lash out for attention. Like many problems with kids the parents can't possibly believe it is their own fault and blame it on things like a behavioral or learning disorder. These kids, of course, get counted in the statistics and their behavior recorded and the stigma grows. And of course, we can't forget the burden on healthcare systems as these kids are placed on useless drugs, raising demand and price.
Then there is also the danger of having a popular disorder such as ADD being blamed for something much more serious on a psychological scale and the child ends up hurting themselves or someone else.
Refusing to admit that parents and teachers sometimes use ADD/ADHD as a scapegoat is just as dangerous as assuming that it doesn't exist at all. The best way to look at it is to admit that there is a disorder (irregular brain and chemical activities can be measured) but realize that too much attention to it can allow poor parents to abuse the system to displace their own responsibilities.
It's easy (maybe not "easy" per se, but "easier") for someone to wash their hands of any responsibility for controlling their child because they're boisterous or naughty, and claim it's "ADHD" - when in fact all children crave attention, and it's the lack of attention and control that sees the child exhibiting symptoms of ADHD without them actually being ADHD.
The need for attention and excess energy is why I believe that removing creative and physical activities leads to more children acting out. This could also account for why it is believed that most (almost all) cases of ADD disappear in adulthood. It wasn't actually ADD. Actual cases persist into adulthood and manifest themselves in many ways from super creativity and workaholic-type attitudes to self-destructive behaviors. I can't find research but I personally think that the end result may be a part of upbringing and personality development.
It's safe to say that the majority of children that are claimed to have ADHD or dyslexia (or both) are not sufferers at all and they swamp the genuine kids, leading to suspicion that the disorders just don't exist.
It kind of reminds me of the South Park episode where one kid got on Ritalin and every parent decided their kid had ADD too anytime they misbehaved. By the end of the episode even the parents had gotten on the medicine and the entire town was acting like zombies and everyone was going to a Phil Collins concert while the pharmacists were sitting around counting their money. Chef was the only one not on Ritalin and when he told the pharmacists that everyone was going to a Phil Collins concert they realized their error and gave everyone "Rital-out" to bring everyone back to normal.
The point is too many parents just slap their kids on drugs and displace the blame. I know in the US a family physician can prescribe mood-altering drugs without a pyschological review first and so if a parent decsribes a hyper kid to a physician they will put the child on a medication without referring them to a psychiatrist first.