Pointless drivel. US refineries soured up (invested in technology to refine heavy/high sulfur) years ago. ANS crude from Alaska is very heavy. Mexican crude is also heavy/sour.
And your point is.....? My guess is that it's still cheaper to lightly refine better, low sulfur oil than to heavily refine a bunch of crap.
That's why ANWAR doesn't make much sense to me -- we should tap it as an emergency reserve, but it ain't worth much more than that..