Sarah Boseley's report in the Guardian about the Lancet genetic study of ADHD, which concludes in the paper that ADHD is not purely a social construct, quotes Professor Anita Thapar, the senior author of the study, as saying that she hopes "that these findings will help overcome the stigma associated with ADHD". She's confident that ADHD is a genetic condition, which, to her mind, shows she was right that ADHD should not be dismissed as being due to bad parenting or poor diet.
Avoiding blaming the parents is commonly used as an argument for a biomedical view of ADHD and other mental disorders, such as schizophrenia. However, it's a misunderstanding of the psychosocial perspective to take this as its implication. Trying to understand why a child becomes hyperactive is several steps away from blaming anyone. There's no suggestion that there's any conscious intention to cause harm and there is no one-to-one causal connection. Understanding reasons is not the same as causal connections.