No worries. I didn't think you were being critical of the choice and thought it a valid discussion point.
I am glad that you raised it.
I know I struggle with what kind of criteria works for non-fiction. Although I also struggle with the issue that I don't feel like I necessarily know even after I read it. I download samples, seek out reviews and still don't necessarily know. My analytical mind tries to bound it by a set of questions but that doesn't help either. So then I think the most indicative criteria is if the author is recognized as literary or has won particular awards. But then I feel like that is too restrictive and might not have worked in this case anyway.