I don't think anyone is arguing that "north american asians are not in tune with popular american culture". Heck, even the asians in asia are in tune with western pop culture.
But it doesn't hold true the other way around. The real question is whether or not North Americans believe that asian americans/canadians are in tune with western culture.
I do believe that on average, Americans' understanding of asian (american) culture is still lacking. Of course, it has gotten better over the years and certain areas that are more culturally diversified will be more in touch than other areas.
Sure, in Toronto (or other areas with a larger asian american population) there may be whites who watch korean soap operas, blacks who watch anime (not the cartoon network ones), and latinos who listen to jay chou, but the majority of North Americans probably have never seen kimchee or an asian who sucks at math

. The unfortunate truth is that larger asian american representations in society are not extremely well spread outside of a few large cities.