I am afraid that it is not true though. First of all it seems a bit unrealistic to expect that divorce happens to the best of marriages. It happens to bad marriages - which also impact children in a negative way. So you would not have to compare the average child with the child of divorced parents, but the child in a crappy situation with the child of divorced parents. And yes, then the differences fade or even disappear.
Also what needs to be considered is the decline in wealth, and social status for children. Poverty is one of many risk factors, that can contribute to all kinds of problems (it is funny though that no government in the world will actively counter poverty effectively, to lessen such effects).
And yes, functional marriages are not per definition good marriages. If hubby is an unemployed alcoholic, mommy suffers from bi-polar disorder, it is still possible for the two of them to raise the kids in a functional manner. But what are the chances Junior or Juniorette
become well-adjusted college-educated people?
To pile up everything is as meaningful as to say that the people of Vanuatu have an impact on the elections of the New York City Mayor.