They're not arguing against anti-fascist work literally at all. It's a bad title honestly; they're probably trying to bring in liberals, for whom that title unfortunately will go hard as fuck, and they absolutely clarify their anti-fascist anarchist position in the video. Their argument is that mere anti-fascism is not enough, in particular that leftist media needs to also tell stories about alternative ways of living, e.g. Le Guin's The Dispossessed.