The throwbacks and adult hard formed vocal chords are of 2 natures:
1. People who were raised without English in Childhood
2. People who flagrantly were raised in the USA to be "happy immigrant" impostors for pity's sake or as an act of defiance towards the USA.
It really isn't that TYPICAL to meet many people of Asian descent who speak perfect english. Whether it is some style of American English or of British "Queen's" English.
Then to diverge further, those who have to scrub clean hard of understanding --the accent of particular American locales, in order to do business in the most NON-OFFENSIVE manner possible in English.
And further, who aren't promoting some other European agenda that is worthy of being Expelled from the USA.
I know I will always be questioned.