I think that because it seems unlikely that we’ve managed to completely eliminate thousands of years’ worth of systemic sexism in such a short time. It’s highly improbable that, with so many things changing all the time, this just happens to be the moment when we’ve achieved a level playing field.
And to address the specific claim, why would being interested in people keep women away from computer jobs? It’s an intensely collaborative field. And why didn’t this keep women out of the field a few decades ago when women programmers were much more (relatively) numerous? If women are generally more interested in people and this drives sex disparities in different professions, why are there so few women in politics, the most people-heavy profession imaginable?