Well, it's not about overeating for one thing. The stuff is everywhere in American food. Assuming you're in the States, you've probably consumed a lot more corn syrup than you think within the past year, and the stuff isn't good for you. Here's an article from the Cleveland Clinic about why it's probably not the best thing to eat:

https://health.clevelandclinic.org/avoid-the-hidden-dangers-of-high-fructose-corn-syrup-video/

Now, as I initially said, I don't know about banning it, but I kinda feel like warning labels are justified, and maybe some other restrictions.

Also… I live in Iowa, and frankly the corn subsidies that have helped cause the corn sweetener explosion are destroying the environment here. It's a lot to get into, but corn production at this scale causes changes to weather patterns. It's a lot.

So, I'd like to see corn subsidies ended, or at least reduced a lot. This would make corn sweetener more expensive and therefore a less attractive ingredient.