"Devoid of a gender, this subject is presumed to characterize all genders. On the one hand, this presumption devalues gender as a relevant category in the description of lived bodily experience. On the other hand, inasmuch as the subject described resembles a culturally constructed male subject, it consecrates masculine identity as the model for the human subject, thereby devaluing, not gender, but women.
Merleau-Ponty's explicit avoidance of gender as a relevant concern in the description of lived experience, and his implicit universalization of the male subject, are aided by a methodology that fails to acknowledge the historicity of sexuality and of bodies. For a concrete description of lived experience, it seems crucial to ask whose sexuality and whose bodies are being described, for 'sexuality' and 'bodies' remain abstractions without first being situated in concrete social and cultural contexts. Moreover, Merleau-Ponty's willingness to describe a 'natural sexuality' as a lived experience suggests a lamentable naivete concerning the anthropological diversity of sexual expressions and the linguistic and psychosomatic origins of human sexuality. In the end, his version of 'lived experience' commits the fallacy of misplaced concreteness, giving life to abstractions, and draining life from existing individuals in concrete contexts."
If gender can be discounted from the "subject" and the discussion of the structures of subjectivity, then gender is just not important, not an essential part of that subjectivity. But this is not even it, because what is actually happening is the assumption of a masculine subjectivity as a norm that can be abstracted away from particulars in a way to erases not gender not masculinity, but the feminine. It is women and women's experience that are elided here.
Butler will go on to say that this simply ignores the known facts about sexual diversity (benign sexual diversity, as she calls it elsewhere), and leaves intact a normative sexuality that center's masculine needs and desires.
Butler names this the fallacy of misplaced concreteness. first, he evacuates the subject of specificity, so that he can then fill it back up with just the specific things he deems as important. An analogy to painting comes to mind: you paint a peach from seeing a bunch od peaches before you or in your memory. First you pull out the form, then you add back the details you find appealing and beuatiful. But that peach is still not a peach in the world, a specific peach, but you pass it off as real, and try to sell it on the market as nourishing.