Over the years, the term "grammar nazi" has been thrown at me, sometimes in spite, sometimes in jest, but always with a degree of sincerity. Invariable though, this "nazi" standard stems from a population of ignoramuses whose idea of "deep" writing is nothing more than a gross abuse of archaic pronouns. (I suppose in some ways it's not too far off from the analytically illogical "wisdom" of Buddhism.) "There thee thine that thou wert thy there" is somehow a profound line of expression instead of an inelegant, nonsensical statement.
In any case, I object to the nazi part of the epithet for several reasons:
It wasn't actually too long ago that fascist ideology drove a world mad, steeped in sanguinary prejudice. Somehow, knowing the historical Nazis make the use of the term heavier. And on principle, I object to the light appellation of loaded terms. It's a bit like exclaiming "Holy Allah!" in front of a muslim, or "Shivering Shiva!" to a hindu. (Or "Bumbling Brahma!") So equating my relatively substantial grammatical knowledge with a bigoted, genocidal government is a bit hurtful.
Usually, the term nazi is used to denote some sort of unerring standard, implying that my knowledge of grammar disallows any room for personal style or expression. But that's not the case! Just because I think that it's stylistically wrong to interchange third-person pronouns "one" with "he" at whim, it doesn't mean that I'm impeding personal style. I mean, what subtle nuance can be derived from using "he" over "one"? (Or "me" over "I" -- one's just grammatically incorrect; it doesn't change the meaning of the statement significantly.) In fact, there is plenty of room for personal style. The problem is, most young writers find amateurish juxtaposition of styles "cool", whereas I would call it bombastic.
Given that I've been studying Japanese and German, I'm already somewhat sensitive to the social/cultural/historical issues surrounding the two countries after 1945. (And I assure you, my interests in Japanese/German go way before the events that started WWII!) So any allusion to axis kinda reminds me of that hellish period in time.
So, please, in future, don't call someone a grammar nazi unless that person is a prescriptivist. :) (Well, maybe only if the person is mean about it.) If you want to find a word to describe the intensity or depth of a person's knowledge, err on the complimentary. Scholar, sage, guru, expert, wizard, lord, master, professor, teacher. All these express that same sentiment of having a wide and precise knowledge. And yet, all of these aren't as offensive as nazi. Even less negative terms would be more acceptable: fiend, addict, junkie, kook. I wouldn't mind being called a "grammar junkie". That suits me fine. But "grammar nazi"? It's not like I have a personal vendetta against hebronics and gaynese or something...