The GI of sugar (sucrose) and HFCS is largely the same. Indeed, the HFCS-55 used in colas actually has less glucose and more fructose, and fructose actually doesn't lead to a blood sugar spike (or, more correctly, a much lower impact), leading to HFCS-55 having a lower glycemic index. HFCS and sugar are both just combinations of glucose and fructose molecules.
HFCS is not worse than sugar unless you're consuming such an outrageous amount that the fructose leads to a fatty liver (which does happen). But if you're consuming that much HFCS, it's only a small amount more of sucrose to yield the same outcome, as of course both have loads of fructose.
The one viable argument to vilify HFCS is simply that it's so convenient and inexpensive (courtesy of massively subsidized corn production) that it led to many more products having added sugars. But people who carefully pour over ingredients looking for HFCS, but treat sugar as wholesome, are usually operating on ignorance.
I agree with you, that would be the exact word I would've used to describe it. Also, since I was a child, I've been scared of pool drains for the treatment system.
