The more you know.
Many foods in the United States are sweetened with high fructose corn syrup (which is very cheap compared to cane sugar because growing corn is very cheap in the United States because of climate, infrastructure, and extensive government subsidies). In soft drinks, the syrup is roughly 55% fructose and 45% glucose.
Table sugar is usually sucrose, which is a compound sugar (disaccharide) comprised of one fructose and one glucose molecule. In many bottled soft drinks, the low pH of the beverage hydrolyzes the sucrose into its component sugars, resulting in a solution of 50% fructose and 50% glucose.
Chemically, we're comparing a 55/45 mixture of fructose and glucose to a 50/50 mixture of fructose and glucose. HFCS has become a bogeyman in American society, but evidence since the 1980s seems to show that, when it comes to soda, the excess fructose isn't nearly as bad as the whole "recreationally drinking 40g of instantly available sugar" part.
Mexican coke does taste different, but it may have more to do with the other flavorants and the bottling process than the source of the sugar.
Here's a fantastic video about this all: https://www.pbs.org/video/everyone-is-wrong-about-mexican-co...
It's not "fructose" vs "sucrose", it's a difference between something that's 50% fructose and 50% glucose (table sugar) and something that is 42% fructose and 53% glucose (corn syrup).