The problem, I think, is that Miya Tokumitsu does everything she can to avoid criticizing capitalism (a charge I think the author would vehemently deny). Capitalism makes all virtues, however we loosely define "virtue", about profit (and if it can't make a virtue profitable, it makes it a vice). "Do what you love" (DWYL) is no exception. Instead of a criticism of how capitalism has corrupted what is arguably the defining virtue of humanity, the emotional and social power of labor, Tokumitsu sees DWYL as the defining characteristic of capitalism, and therefore not a human construct. Her interview, Why ‘Do What You Love’ Is Pernicious Advice, carries on this theme.
The fundamental point of the interview comes near the end: "[O]ne of the things I want to do is celebrate the job that just pays the rent." But just paying the rent, not DWYL, is the fundamental capitalist virtue. It is the essence of alienated labor, a concept Marx writes quite a bit about. When you work just to pay the rent (and notice "rent", paying the parasitic landlord class), your labor is literally alienated, cut off, detached, made external. Working just to pay the rent reduces our work to the "cash nexus". I see nothing at all wrong with Marx's goal, to make labor "not only a means of life but life's prime want." All of us should be doing what we love; the fact that we cannot is a failure of capitalism; it is not that doing what we love is itself disreputable.
Of course, capitalism does try to digest every virtue and make it about cash, and DWYL is no exception. Tokumitsu talks about how capitalism tries to corrupt DWYL: the corporate PR fakery, standards that employees should always look like they're happy, the want-ad insistence that candidates be "passionate" about janitorial work, the idea that if you're doing what you love, you should not expect to be paid in actual money. But Tokumitsu draws the wrong conclusion from these attempts: capitalism is trying to assimilate, corrupt, and ultimately destroy the fundamental virtue of socialism. Socialists can certainly resist the corruption of this virtue, and critics can certainly argue that corrupting the virtue of DWYL produces more, not fewer, contradictions, but arguing that we should do away with the virtue entirely, and accept absolutely alienated labor as the ultimate standard of good would do nothing but hand capitalism an unearned victory.
Socialist theoreticians should, of course, valorize the proletariat, whose labor is absolutely alienated. But we should valorize the proletariat and the alienation of their labor not because alienated labor is the best form of labor. Instead, we should valorize the proletariat because the absolute alienation of their labor is, as Marx argues, the fundamental contradiction the resolution (sublation, aufheben) of which produces revolutionary consciousness.
See also: In defense of "Do What You Love"