He's saying that the research wasn't actually using high-fructose corn syrup (which is a glucose-fructose mix), instead it used 100% fructose. So scientifically, the study results can't be applied to HFCS.
More specifically they can't be used to differentiate HFCS and regular sugar since they both contain fructose in similar quantities.
If fructose is bad it would suggest that the fructose in HFCS and sucrose are bad as well.