If the south Indian's English is native, or one of several "native" languages for him, you could get "bleed-over" from his other languages (that's how bilinguality works; trust me, I live among a language majority of Finnish-speakers and get to see how that's affected the Finland-Swede minority's Swedish). Maybe in Hindi or whatever, the style you call "bad" in English is all the rage? I dunno.
Whereas the Chinese, in my hypothesis, *naturally* writes "crisp clear sentences that get to the point" -- that's what you *do* in an essentially alien language; you write as if everything were a school essay, because to you, it pretty much *is*.
And I wouldn't put Raj English on a level with "Ebonics" -- there probably is a "Raj English Ebonics", the speakers of which are looked down upon and seen as bumpkins by genteel speakers of "High Raj English", and you've met only the former (because the latter are well-enough off home in India not to have to emigrate to the States)...
Oh sure, this is all pretty much conjecture, but it seems to stand to reason. (Or, to say the same thing in less scientificative terms, it "feels intuitively right".)
P.S: Never even tried the Bhagavad Gita, but I *do* feel rather OK with Ashton... :-)