Note to devious mouthpieces of Big Food ("Always with the negative waves, man."):
Something needn't the sole cause of a problem to be a cause of a problem. So when you fault any attempt to curb consumption of sugary sodas because soda isn't the sole cause of obesity, you're just obscuring the truth.
No, sugary soda is not solely responsible. The problem and its contributors are varied, confusing, and sometimes conflicting.
But sugary soda is unique — or rare, at least — in how its negative influence is practically untouched by any positive counterbalance. Pizza, for example, isn't healthful, but advocates could argue that it's got vegetables and protein, and they'd be right, at least about that.
But the most one can say in favor of sugary soda is that it's refreshing. And "refreshing" hardly counters the weight of obesity on public health.
So while we try to grasp all that needs to change to counter this public-health threat, there is no better place to start.
Even if it's not the only cause. No one says it is.
(It's true I'm not linking to the forces that trot out this argument. This is because I don't want to give them any traffic, not because I'm addressing an ill that doesn't exist.)