"Of course, differences exist at the individual level, and this doesn’t mean environment plays no role in shaping us" is known as the CYA caveat. 

Consider your own last two sentences. For example, there was a time when women were viewed as biologically unable to be in medicine. This, of course, was backed up with many barriers into medicine and misogynist experiences within the field. We now know that the biological "fact" is false and it was a cultural shift in society and within medical education that opened the door.

As for "why"? First, it is important to contest and verify/disprove the latest menu of 'biological facts' used to explain the gap. And then consider what cultural attitudes and barriers remain. 

No, a newspaper op ed is not a literature review and that is the problem when it is presented to be "science".