I think you are reading too much into it. I also encounter similar attitudes from time to time, but they appear to be rather unreflexive expressions of self-righteousness and gang mentality - if we kick their ass - good, if they kick our ass - bad". Their reflex is simply to kill anything perceived as a threat, as well expressed in a the following bumper sticker: "If you love something, set it free. If it runs away, hunt it down and kill it."
The discourse that you describe requires empathy with people other than members of one's own gang (without which the phrase "Vietnamese children should enjoy exactly the sort of sheltered childhood like their" is meaningless) - and these folks are basically incapable of such emotions, as far as I can tell.
> Material questions of exploitation and oppression are thus
> ideologically turned into cultural ones of "differences" -- between
> "the civilized" and "the barbarians."
That is a good observation, indeed. I would only add that the "oppressed" are as guilty of this transformation as the "oppressors" since they eagerly and willingly accept cultural labeles that "justify" their own oppression in the oppressor's discourse. The hip-hop crowd calling Black people "niggas" is a case in point (all the hip hop fans out there - please spare me the drivel that this is an act of "protest," that this is not "true" hip hop, or that I am missing something). In many developing countries, extreme nationalism and regression to obnoxious "native" customs (such as patriarchy and sexism) serves as a symbolic rejection of Western influences - but the tragedy is that they usually reject the good aspects of Western influences (such as liberal democracy or equal opportunity) while craving for the most depraved ones (such as consumerism or power arising from wealth and access to technology).
Wojtek