Czarena Crofcheck, Ph.D, a food science professor at the University of Kentucky, says "The body is actually really good at processing sugar, compared to alcohol, so sugar doesn’t affect a hangover. It’s just that sugary drinks are so much easier to drink, so you can lose track of how much you’ve had and push it too far.
But rather than trust “someone on Reddit”, or even a food science professor, at their word, I would like to see real evidence. I couldn’t find any with google, and I bet Eleanor Steafel has none either. My guess is that she was told it by a PR person for a crémant producer