"Grammar nazi" is an Anglo-American internet colloquialism which means a person who is overly enthusiastic about correcting someone's word usage. I don't think anyone was accusing you of being a Nazi or alluding to that rather unfortunate series of events in German history.
I am quoting this because it says it better than I could.
Absolutely no offense was meant to anyone in particular or any nation or people in general.
As getupgetout stated, it is a fairly frequently used term meaning someone who goes out of their way to point out a grammatical error, whether perceived or real.
And it was directed towards myself.
Please accept my apology in this matter. I sincerely meant no offense and, in all seriousness, was not even paying attention to the flag icon in your post.
I was going to say that I will try to be more careful, but, on reflection, I will say instead that
I
will pay more attention when I post and bear in mind the fact that words and phrases can have
different meanings in different places.
Once again, I am sorry. No offense was meant and I am incredibly ashamed and embarassed by any I have caused.