>But my question is, "why?"
Because they view the issue as being conditioned by today's society; while I admit it's not best to jump to such a conclusion without serious critical investigation, I find it tiresome that you call it "ideological" - as if an explanation which specifically seeks to avert any critical view of the development of Western society isn't itself "ideological". Is it the result of the sexism of patriarchal society? Let's find out by consulting sociology, critical theory and philosophy. A critical understanding of the issues wouldn't stop at merely controlling for the pay gap, for instance, it would ask why women negotiate less, why they tend to work fewer hours etc. Roswitha Scholz put it well:
>We have also to account for the fact that under capitalism reproductive activities emerge that are primarily carried out by women. Accordingly, value dissociation means that capitalism contains a core of female-determined reproductive activities and the affects, characteristics, and attitudes (emotionality, sensuality, and female or motherly caring) that are dissociated from value and abstract labor. Female relations of existence — that is, female reproductive activities under capitalism — are therefore of a different character from abstract labor, which is why they cannot straightforwardly be subsumed under the concept of labor.
>[...] Prior to this, women were largely regarded as just another variant of being-man, which is one of the reasons that the social and historical sciences have throughout the
last fifteen years stressed the pervasiveness of the single-gender model upon which pre-bourgeois societies were based. Even the vagina was in the context of this model frequently understood as a penis, inverted and pushed into the lower body. Despite the fact that women were largely regarded as inferior, prior to the development of a large-scale modern public, there still existed for them a variety of possibilities for gaining social influence. In premodern and early modern societies, man occupied a largely symbolic position of hegemony. Women were not yet exclusively confined to domestic life and motherhood, as has been the case since the eighteenth century. Women’s contributions to material reproduction were in agrarian societies regarded as equally important as the contributions of men.