I think it's less rigid thought patterns (I mean, insofar as you can judge from three books, a statement, a few articles and a bunch of interviews) than an ingrained sense of self-righteousness which means there's only one way of viewing things and a single perspective on events. She's clearly most comfortable with her and Tim as the perennial victims of circumstance, trusting, free-spirited children of nature who are mistreated by a traitorous, indifferent world.
Anything that, like CH's story, positions them as conniving, criminal, or actively manipulating circumstances to their advantage, is perceived as 'vitriol' and 'a threat' because it attacks her worldview and her view of herself as a lone free spirit among the grey office-based drones who don't hand-dig their beloved ancient sheep a grave or who tamely go into emergency council accommodation and get jobs when they become homeless. Tim is key to her worldview, too, obviously, as someone she can depict as a fellow free spirit. (Whereas what they appear to have in common is being grifters and a disinclination to work for a living in any longterm way.)
If this were a novel, I'd make Moth have an affair now. Possibly with someone in the publishing world. Or a deep undercover journalist who appears sympathetic?😀