If you had the energy to do so, you could try to replicate his results, i.e. buy a Mexican Coke, an American Glass Coke, and an American Can Coke, and decant them all into glasses or cups at home, then see if you can taste the difference.

If all your brain/tongue perceives as horrible is the taste of the aluminum can, you could always switch to buying Coke in glass bottles, which are more expensive than cans but still cheaper to buy in bulk than Mexican Cokes, and can be found at most grocery stores.

Or, if being limited to Mexican Coke means it reduces your overall soda consumption because you're only able to drink it when you're near a Home Depot, keep doing what you're doing. You'll probably be healthier for it.