Let's go through it step by step. Feminism begins with the liberal idea that we can be more or less human depending on how autonomous (self-determining) we are. Therefore, if women as a group are less autonomous than men as a group, if they don't have the same "agency" as men, their status is not fully human.
Second, autonomy means being unimpeded in choosing what to do or be. Our sex is something we don't get to choose, so gender becomes something that makes us less human. If you believe that women are an oppressed class, deliberately denied autonomy, then it makes sense to think that women are the "sex class" - the ones who bear the burden of having a "sex" attached to them, unlike men who form the "human" class.
Third, if you believe that men have more autonomy than women, and are therefore a dominant class, it's reasonable to think that men have organised society to uphold their own power and privilege over women. Why would men do this unless they harboured negative feelings toward women? And how could women assert true self-determination in a society organised in a systematic way to deny them autonomy? And how could things change without a revolutionary, radical overthrow of the whole system?
Enter "Twisty", the "spinster aunt" who runs a popular radical feminist website called "I blame the patriarchy". Her great virtue is her willingness to take political positions which flow logically from the theory. She is an intellectually consistent feminist.
When Twisty tells us that women who attempt to be physically attractive "get sucked into the Femininity Hole, never to be human again", she means it. It fits the theory, that gender is something which impedes our autonomy and that this loss of autonomy deprives us of human status.
There is a logic, then, in Twisty insisting that women ought to reject femininity. Similarly, there is a theoretical consistency in Twisty maintaining that women in a patriarchy, lacking agency as they must, cannot truly consent to sex. Twisty herself explains this as follows:
... in a patriarchy, the cornerstone of which is a paradigm of male dominance and female submission, women do not enjoy the same degree of personal sovereignty that men do. This oppressed condition obtains a priori to all other conditions, and nullifies any presumption of fully human status on the part of women. A woman, therefore, cannot freely "consent," because her will is obviated by her status as a subhuman.
But if sex is rape then men are ... rapists:
all humans are conditioned to despise women. A woman ... can never be humanized. The American legal system, as a matter of fact, effectively outlaws humanity for women. It does this in many ways ... One of the most insidious is its assertion that women are in a perpetual state of 'consent' ... It is by this cunning method ... that the future of rape as the cornerstone of human social order is secured.
... It is by popular demand that, decades after American women were first deemed "liberated", the countryside remains infested with unjailed rapists. These freely roaming rapists are patriarchy's enforcers.
Now, as admirable as I find Twisty's commitment to theoretical consistency, she has arrived at a difficult position. First, it's not an easy politics to sell to young women. Twisty herself is fully aware of the problem; she says of the idea that women cannot freely consent to sex that,
I suspect that the rampant unwillingness among young feminists to deny this grim truth stems from the wholly untenable position into which it thrusts'em. They're young, they're fit, they wanna boink; who can blame them if they just aren't ready to accept that nothing short of an exhaustive, uncompromising overthrow of the social order will put them in complete control of their own selves?
Similarly, Twisty explains the existence of an alternative "sex positive" feminism as follows:
It reassures women who fear the burden of true liberation that femininity is a legitimate identity.
The burden of true liberation? Can you really have a burdensome liberation? Isn't that a tautology which suggests that the wrong sort of liberation is being aimed at?
There's another problem with Twisty's consistency of theory. It's not only difficult to live by in practice, and unappealing in what it demands, but it doesn't seem to correlate well to reality. This is what the more moderate feminists object to. A feminist blogger named Holly wrote a post criticising Twisty, partly because it's just not her own experience that the average man is a woman hating, privilege enforcing rapist:
Some of my best friends are men. The vast majority of the men I see every day are kind, hard-working, intelligent people who respect women. In my world at least, hooting fratboys or growling wifebeaters or crazy fundies are outnumbered 10 to 1 by ordinary Joes doing the best they can to be decent people.
Nor does she feel like she's a member of an oppressed subhuman class:
Call me a rich white het cis privilegebunny, but I don't feel very oppressed. Sometimes insulted, sometimes worried, sometimes concerned for the oppression of people in other places, but in my own life I just don't feel the boot on my neck. At work, at school, socially, nobody acts like I'm less than human or tries to enforce the Patriarchy on me directly. For me, in my daily life, I don't feel like being female is difficult or painful.
So Holly is more of a realist than Twisty. Unfortunately, she lacks Twisty's intellectual rigour. She sticks with the feminist theory, even as she rejects the political positions drawn logically from the theory.
For instance, she welcomes a comment from a male commenter on the basis that,
Your hereditary membership in traditional oppressor classes doesn't make you personally a bad person unless you choose to be, and it shouldn't exclude you from dialogue.
Holly believes, therefore, in the underlying theory that men have acted as an oppressor group dominating women. She writes too that the proper focus of feminism is "advancing the cause of female strength and independence" (i.e. autonomy) and that gender is a source of oppression:
I'm a feminist. I really am, dammit. Our culture is permeated with weird ideas about femininity (and masculinity!) and it desperately does need to change.
So we're back with men as an oppressor group denying women autonomy via an oppressive construction of gender. This despite the fact that Holly has just told us that she herself doesn't feel oppressed as a woman and that the men she meets personally are hard-working people who respect women.
Holly doesn't want the political positions drawn from the theory to become unpalatable or unrealistic; she's more of a pragmatist than Twisty. She nonetheless shares with Twisty the same basic political theory.
I don't think that conservatives should rush to support a Holly type feminism just because it's more pragmatic and less overtly hostile to men. In some ways, a Twisty feminism teaches us more by unfolding the logic of feminist theory for us.
If we don't like where the theory takes us, then we ought to critique the theory itself, rather than the political positions it leads to.
We ought to consider the following questions:
a) Is it true that our status as humans fluctuates, or is it something permanently invested in us?
b) Is autonomy really the one overriding good? Is it the organising principle of society? Or is it something to be held in balance with other important human goods?
c) Are human relationships really structured around a contest for autonomy and power? Is this the core meaning of family relationships? Of communal traditions? Of manhood and womanhood?
d) Have the actions of men throughout history really been to the detriment of women and for selfish purposes?