In her slender but merciless new book, Jessa Crispin pours petrol over pretty much the entire surface of 21st-century feminism, and then gleefully sets it alight. Boom! Up it goes, leaving behind only scorched earth. What she hopes will grow in its place isn’t completely clear. “I know! I know!” she wails, when I tell her she offers more questions than answers. But having no desire to be an activist, she doesn’t see it as her business to fix the patriarchy. “Maybe this sounds disingenuous, but I was writing for myself,” she says. “I just wanted to be clear about what I believe.”

The book is called Why I Am Not a Feminist, which is, of course, a lie as well as a provocation, for its author’s feminism runs through her veins like blood. Crispin’s principles, however, have their roots, radical and angry, in the second wave of feminism, not the third: she, for one, is not about to renounce the likes of Andrea Dworkin and Shulamith Firestone, whose uncompromising books she has, incidentally, actually read.

Trump is the apex of predator culture. To get rid of him we have to change society completely

What she disdains, then, is what she deems lifestyle feminism: a bland, ultra-inclusive marketing exercise that demands absolutely nothing from those who buy into it save for to ask that they use the word “feminist” as frequently as possible, preferably while looking utterly adorable. “Dior has this $600 T-shirt that says on it: ‘We Should All Be Feminists’,” she tells me, when she talks to me on Skype from New York (where she is ill and rundown, her pink kimono almost matching the colour of her feverish cheeks). “But what does that say about the person wearing it other than: ‘I can afford a $600 T-shirt’? Feminism has been entirely co-opted by consumerism.”

The new feminism, which is not really feminism at all, is by Crispin’s telling as shallow as a martini, and a good deal less good for you: “This is a T-shirt you can wear in order to cloak your bad behaviour, to let you think of yourself as some kind of political hero or rebel without you actually having to do anything.”

What, she wonders, is the end result of so many younger women choosing to call themselves feminists? “It’s about individualism, and self-achievement. It’s about pop stars and television and narcissism. It’s not about subsidised childcare, or institutional and structural social change. It’s meaningless.” This self-obsession and ideological laziness extends, she thinks, even to their reading matter. “Roxane Gay [the US feminist writer] is on the record as saying that she hasn’t read Andrea Dworkin [the anti-pornographer campaigner], and that we don’t have to, either. Really? Isn’t there work and sacrifice in being a political person?”

Facebook Twitter Pinterest ‘It’s meaningless’: a T-shirt won’t change anything, says Crispin. Photograph: SIPA/REX/Shutterstock

She despises the way some women cherry-pick the movement’s intellectual history. “When we talk about it now, the people we remember are these bland figures like Gloria Steinem, whose role was always to be the intermediary for men. She sells out her feminist sisters. What was that thing she said? That girls who supported Bernie Sanders only did it because the boys were with Bernie? Well, fuck her.”

Crispin looks out at the world and sees a hyper-masculinised realm in which women must mimic men if they’re to survive, let alone to rise in an upwards direction. “I realise that using words like ‘masculine’ and ‘feminine’ in this way can get you into trouble these days,” she says. “But where are the [feminine] values of community, care and empathy in our modern world? Their absence doesn’t seem to bother a lot of people.”

Once some women reach a certain level of independence, she observes, they fight only for themselves. Money, as she notes in her book, is a quick route out of the patriarchy: pay another woman to do your housework, and you’ll be free to, well, make more money. But even those with the best of intentions – those singular sisters who would rather take a hammer to things than politely “lean in” – rarely end up changing the culture of any given industry.

“Good intentions are nothing against the system,” she writes sombrely. And then, more terrifyingly: “The system is older than you. It has absorbed more venom that you can ever hope to emit. You will not even slow it down.” She would also like it to be known that not getting what you want is not, by any stretch of the imagination, oppression.

She finished writing Why I Am Not a Feminist before the victory of Donald Trump, for which reason her book does not describe how, on election night, she found herself sobbing in a Chicago restaurant. Still, given what she thinks both about the establishment, and the superficial ways of those who purport to stand against it, I wonder if she believes Trump’s administration will ultimately make much difference to the lives of women. (I like her book: it’s clever and droll and righteous. But it also has an in-built fault, which is to make the reader believe that pretty much all resistance is futile.)

Facebook Twitter Pinterest ‘Gloria Steinem’s role was always to be the intermediary for men. She sells out her feminist sisters’. Photograph: Richard Saker/The Observer

“Well, he is already destroying lives through military action and his Muslim ban,” she says. “But to me, he didn’t come out of nowhere. He is the apex of predator culture. To get rid of him we have to change the culture completely.”

The Women’s Marches which followed his inauguration seemed to her to lack focus. “This is a repeated problem with the American left: the lack of clear goals. Those marches were celebratory. They were good for the heart. But we’ve had [municipal] elections in the US since then where the turnout was, like 15 to 20%. During the Women’s Strike [on 8 March], I saw a journalist ask a woman what she was going to do instead of working. She said: ‘Oh, I’m just going to do something empowering like watch Buffy the Vampire Slayer!’ I mean, come on! Let’s do something, here.”

Crispin is a university drop-out in her late 30s with a sideline in “creative tarot” (she offers readings via her website). She made her name at Bookslut, the radical website she set up while working in a boring job at Planned Parenthood, which she closed last May, after 14 years. “The literary culture just seemed to be increasingly toxic and blind,” she says, wearily, of its demise. “We felt increasingly lonely as online spaces became professionalised, more focused on money, branding and getting attention from the New York Times.”

But if Bookslut was hard work, now it’s gone perhaps she finds herself with less, rather than more, freedom. Given her reputation, getting commissions elsewhere isn’t exactly straightforward. “For the most part, people don’t want me to write the things I want to write. It’s frustrating. But I also have this… uncompromising nature. It’s tragic, really.”

Not every woman, as she writes in her book, wants the freedom to work 80 hours a week while “some young Harvard asshole” gets promoted above her. But opting out isn’t easy, is it? No one can live on fresh air, not even Crispin. “William James [the American philosopher] has this line about accepting vulnerability and economic difficulty in order to have an un-bribed soul. I feel like the rewards I get for the kind of life I lead are greater than they would be if I did choose to compromise. When you do your taxes, and see the total amount of money you make in a year, it’s easy to confuse that with value. But what you earn does not represent your worth.” Is it hard, sometimes, to keep going? “Yes, it is hard. You have bad days.”

Facebook Twitter Pinterest ‘No focus’: protesters in pink hats on a Women’s March. Photograph: Henrietta Wildsmith/AP

And what about the other womanly compromises she might make? What about, say, marriage, children, all that? She grew up in conservative Kansas, the daughter of “a patriarch” and a housewife (as well as being a patriarch, her father ran his own pharmacy). “I was raised to be a wife and a mother,” she says. “Those were the only expectations, and either you 100% swallowed them, or you 100% rejected them. I rejected them. For whatever reason, I have always been the person who sets everything on fire.” For a while, she was estranged from her family. Now, they don’t talk much, but when they do, things are civil.

Still, she won’t be doing the right thing so far as they go by getting married any time soon. “Even if I fall in love, I won’t marry that person – unless, say, my kidneys failed and he had health insurance. So far as children go, last year I wrote this essay about Rebecca Traister’s book, All The Single Ladies. Traister talks about how empowered single women are. Are they, really? Actually, they’re incredibly vulnerable and living in precarity. Let’s not pretend otherwise. But the real reason for writing that essay was that I was then trying to work out whether or not I wanted to have a child as a single woman, and I realised I can’t. I’d be emotionally, physically and financially alone. There are no support systems in place for someone like me.”

As for the endless business of waxing and dyeing and buffing – fragrant 21st-century feminism says: you’re worth it – sometimes she bothers and sometimes she doesn’t. “When I was living in Texas, I dressed in men’s clothing all the time, to the point where I was called sir,” she says. “It wasn’t a gender thing. It was just nice to exist outside that space of being examined. We all talk about the male gaze as if it’s this eyeball in the sky following you around. But you can evade it – it’s not that hard. I don’t think everyone has to put on a burlap sack, but rejecting that stuff for a while is useful. Now, when I do put lipstick on, I have a better understanding of why I am.”

Facebook Twitter Pinterest ‘Even if I fall in love, I won’t marry that person – unless, say, my kidneys failed and he had health insurance’: Jessa Crispin. Photograph: Circe Hamilton/The Observer

In life, as on the page, she makes a magnificent show of being tough. But is she really? She emits a strangled laugh. “If ‘tough’ can encompass crying in the shower then, yes, I am.”

Well, now I’m going to have be a little tough myself. If our marches are pointless and our workplace aspirations without worth, what should we do instead? She can’t be allowed to get away with writing a feminist manifesto with no plausible suggestion for the society of the future.

“You can start by all divorcing your husbands!” she says. For a moment, I wonder if she’s joking. But, no. “There does have to be a process of understanding the way you participate in these systems of oppression. Marriage’s history is about treating women as property, and by being married you’re legitimising that history.” Another good start would be to remove your money from the big banks and put it in a small, local credit union instead, “even if you only have $80”. Above all, maybe women should start listening to one another again.

Crispin is disciplined when it comes to reading about herself on the internet: she doesn’t. “Somebody is always going to take you down. What passes for debate now is geared towards destruction. That’s why we’re going round in circles. No one develops their thinking. You have to learn to have an argument, to encounter a different opinion and then to figure out how to argue against it rather than just telling the other person to shut up. It’s about rhetoric, logic, detachment.” She sighs. Another reason for writing the book was so she wouldn’t have to talk about any of this stuff ever again. But so far, nobody seems to be going along with that.

Why I Am Not a Feminist is published by Melville House at £12.99, or £11.04 at bookshop.theguardian.com