ADHD is defined in the DSM-IV and now -5 as presenting with predominantly hyperactive tendencies or with predominantly inattentive tendencies (or combined, presenting both).
I didn't read it as the author saying that males don't present with inattentive type. Rather, I thought she was saying that, since women don't as often present with hyperactive type ADHD as males, the general message is "girls have less ADHD." Which, then, can impair seeking a diagnosis for a female that has the disorder, since there's a general bias to look for other things first.
As far as I've ever understood the inattentive type goes under-diagnosed for both sexes, as it's not as disruptive to classrooms, where most diagnoses are started for children. The hyperactive type may be more often diagnosed based on comparisons between US and European diagnostic criteria -- the European model results in fewer diagnoses[1].
The author discusses this early in the piece:
[Dr. Ellen Littman attributes under-diagnosis in part] "to the early clinical studies of ADHD in the 1970s. “These studies were based on really hyperactive young white boys who were taken to clinics,” Littman says. “The diagnostic criteria were developed based on those studies. As a result, those criteria over-represent the symptoms you see in young boys, making it difficult for girls to be diagnosed unless they behave like hyperactive boys.”
[1]: https://en.wikipedia.org/wiki/Attention_deficit_hyperactivit...