Saying that you expect a different tone because he is currently writing in English, in public, for an international audience is not the same as saying that his culture of origin in no way influences his communication style.
That's like saying because my mother is now an American citizen, she should obviously no longer have a German accent. You may personally feel she has some obligation to do her best to lose the accent, but regardless of the standards you would like to see imposed on other people, most people remain influenced for life by things they grew up with.
Ah, I think I completely misunderstood you. When I read
> From what I gather, some of this is cultural. His country of origin is just generally blunt and direct about things.
I assumed you meant
> His country of origin is just generally blunt and direct about things and that is sufficient justification for his using a rude tone on a public mailing list
and I was also rather confused because this seemed to be a non-sequitur. I thought you had indended to reply to one of the other comments criticising his tone. On rereading it now seems that you were saying that
> His country of origin is just generally blunt and direct about things and this is why his is good at calling out bullshit when he sees it
Sorry for a double misunderstanding. If I hadn't made the first one I wouldn't have made the second one either.