Dynm, i can tell the difference between hfcs and non-hfcs soda. I get blockage near the vocal cords about 5 - 15 minutes after consuming it, so there's definitely something worse than sugar about it.
Difference in trace constituents, triggering allergy, is completely plausible. But either way, it is the fructose identical in both that is actually poisoning you.
For myself, I get tiny blisters on the backs of my hands and neck from cranberries. And, onions make my sinuses bleed. Indigestion is more common.