191: Against Many a Defense - The most perfidious way of harming a cause consists of defending it deliberately with faulty arguments.
This aphorism is, I think, key if we are to make any sense of Nietzsche's hyperbolic and offensive statements. Nietzsche toys with our expectation that he should be arguing for his perspective by engaging in the very forms of argumentation he disagrees with, successfully parodying them by showing what a lack of reason they exhibit and pointing towards other conclusions regarding the subject at hand. So, for example, in 140, entitled "Too Jewish", he utilizes the tendency to justify behaviors on racial lines to make a point about the heritage of Christianity and its tendencies, in tandem with the surrounding sections. He points towards (I think this is the best way to characterize his style of argumentation) the absurdity of anti-Semitism by making clear, again and again, the affinity between Christianity and Judaism while appearing to be engaging in purely racist argumentation.
A similar, and altogether bizarre example of this is found in section 145, "Danger for Vegetarians"; here he engages with the common Orientalist perceptions and anti-Irish sentiment (which seems rather odd, since he isn't English). His first line is a bizarre bit of syllogism: "A diet that consists predominately of rice leads to the use of opium and narcotics, just as a diet that consists predominately of potatoes leads to the use of liquor". Here Nietzsche is engaging in the sort of racist talk about tendencies and diets that was not necessarily uncommon in this period. The reasoning is shown to be laughable, and Nietzsche uses this to make a greater point about dietary rules in general: the religious dietary restriction is also a method for control. The guru would like to enforce the rule of vegetarianism as law because it would further increase influence; the talk of narcotic effects, I think, should be taken less as a literal statement of the effects of foods and more as a statement about the religious content being discussed.
The difficulty in interpreting such sections is that Nietzsche parodies are so subtle that it requires biographical knowledge to determine where he is telling the truth and where he is engaging in parody. The situation is further complicated when we consider the different standards of what was and what was not considered acceptable language: his use of the term "Oriental", for example, would likely not have struck his peers as overly offensive, even though it is questionable to us. Nietzsche surely knew that misunderstandings would occur, and seems to have strategically placed hints such as section 191 as well as others about humor and lightness, to suggest to us that there his ridiculous arguments and questionable statements are only preliminary stages upon which he is engaging in more complex reasoning.