One doesn't have to read very far in Gibbon's account of early monasticism to realise that he takes a very negative view of the subject.
Indeed, in the introduction of her translation, The Desert Fathers: Sayings of the Early Christian Monks, Benedicta Ward says: "Some of the monastic extremes of physical discipline, such as going to the limits of existence with as little sleep, food, drink and companionship as possible, were a cause for wonder, then and later, not always of a complimentary kind." (page xi). In her footnote to this comment she particularly singles out Gibbon as an example. The translation (but not the introduction) can also be viewed at Google Books. Since the book is a compilation of sayings with the occasional background story, the fact that some pages have been skipped don't make so much of a difference as it usually does.