One of the reasons Calibre has become the de-facto gold standard for ebook managers is that he always tried very hard to help users, who are often non-technical (they are largely just "book people").

I think he's just a bit fed up with geeks who like to question everything at every turn; he is not the sort of person you should look to for philosophical debates on the state of software. For years, Calibre got a bad rap for the interface not looking "cool" enough, meanwhile he was busy actually helping people do what they want to do with their books, for free. Plus, his mother tongue is not English and some communications can come off as brusque even when they are just meant to be direct and to the point.