It comes down to a debate over how much you can "nudge" people to make the right choices.
We talked about the NY soda ban here. In general, I'm in favor of nudging. The issue of paternalism is complicated. On the one hand, expert wisdom is often wrong or even foolish. In practice, the state has historically been more inclined to want people to do things like melt their cookware to produce shoddy steel in their backyards (Mao) or have all children in the country learning about "nos ancetres les Gallois" (France).
New York's faith in humanity must be low indeed if it thinks only the most blatant coercion can get people behaving differently. Whether collectively or alone, people are hopelessly incompetent, is the message Bloomberg's soda ban sends. A more accurate way to put it might be that people are incredibly malleable, open to having their decisions swayed in terrible ways by factors that are out of their hands. The difference is slight, but in the small gap between those two statements lies an opportunity to move people in the right direction without taking away their freedom. Just because we often fail at making good decisions doesn't mean we can't.
But on the other hand, people can be self-destructive, short-sighted and impose serious costs on others. All that obesity results in staggering medical costs too. The core liberal idea of autonomy often does not work very well in practice. The Aristotelian view is more realistic about weakness. We have to be habituated to virtue, he said, learning by doing.
And is one example of where we need a golden mean between forcing people to act in certain ways and being completely indifferent to how people behave.