It's a substance that creates craving and addiction and provides the body with no real nourishment, and consistent long-term consumption of it will lead to a degradation of one's health. Try stopping cold turkey and see how you feel after a couple of days.
It's like cigarettes, in that even with daily use, you may not see the long-term consequences for years, but they're there and they come.
It's not the only issue that is creating an obesity epidemic in America, but it's a significant one. If you go back 20-25 years, you wouldn't see such a high-percentage of rotund individuals. Just look at old TV news clips, or newspaper photos, it was much more rare.
But with Bloomberg's plan, I don't see what would stop anyone from buying two 16 oz. drinks of coke instead, so I really wonder how effective this would be.
Frankly, I'm all for individual rights, but how about a Surgeon General's warning instead on the side of every bottle of coke and diet coke (aspartame isn't any better), stop the marketing of it to kids and distribution in school settings, and education and recovery plans to assist anyone who wants to escape a daily high volume sugar intake permanently.
We know prohibition doesn't work, and despite the irrational execution of America's "war on drugs", I'm not advising it. But c'mon, lets stop pretending that there isn't a serious problem with is being marketed and sold as consumable food in America (and it's not just sugar), and actually do something about it.