I suspect Lustig knows that (notwithstanding the fact he says something similar in his lecture, and Taubes repeats it), but decided it's not important for his thesis. Or, at the very least, he doesn't want to wade into the sucrose/HFCS debate. Evidently, he thinks the fructose is sufficiently available in both to be problematic. I'd be super interested in your wife thought something different. I suspect Lustig would too.