Maybe some people think like that, but prevailing academic feminist thought does not resemble what you're describing.
Modern feminism sees gender as a continuity rather than a boundary, and looks at how social gender constructs support systems of power. For example: why are men often stigmatized for becoming grade school teachers? The modern feminist (at least one with the theoretical bent you're describing) sees this as oppression and tries to come to grips with it by looking at the social constructs of masculinity and femininity, and more specifically in this case of maternity and paternity.
In a society where women are caregivers/mothers and men are builders/leaders, then individuals who do not embody those characteristics are marginalized and oppressed. And the marginalization goes both ways. In a society where men are stigmatized for embodying femininity, it will be true that women will be stigmatized for embodying masculinity.
The problem is discussed in a far more multidimensional fashion than you're describing. Marxism is used as a tool for analysis, as are many other ideologies, but is certainly not the dominant force. A (good) academic paper that uses Marxism for analysis will often say, "I'm using Marxism to analyze this topic because I feel that in spite of shortcomings A, B, and C, that I can use it to tease out this subtlety..."
I would go so far as to say that you are unapologetically building a caricature of what you're describing. Why? Because it's almost never the case that you can take an entire group of people, (in this case, the 'American academy') and apply such a sweeping generalization to their way of thought.
In fact, the modern feminist would suggest that it's your absolutist way of arguing that perpetuates this kind of system. When you say that a certain group thinks in a certain way (especially one so easily problematized), you are promulgating the same type of thinking that leads to, "Men shouldn't be teachers." The idea is that when you look at any crowd of people, do you understand that what you're looking at is not some group entity but in fact a very complex interweaving of social dynamics--personality, class, gender, sexuality, family, culture, race, age, height, weight, and all of the intersections thereof. Or do you think you have that group 'figured out' and pigeonholed? Once you have the group pigeonholed, you've denied the individuality and agency of the people in that group.