No, you're reaching here. Encourage is exactly what the over-size soda container rule does. It doesn't prevent people from consuming as much sugar water as they like - which is what enforcing would do. Rather, it makes the person have to actively choose to consume more than, I think, 24 ounces per container. You're cries of liberty in exchange for security seem silly in this light.
You can go ahead and be against it, but at least come up with a worthwhile reason. While you're doing that, the rest of us will be secure in the data that shows that portion size matters: the larger the plate, the more you eat whether you want to or not.
In fact, I'm going to reframe this whole discussion.
The container ban is a curb on corporate manipulation of unwitting consumers who have been tricked by their own fallible psychologies into paying far more than they should for a product they don't even want. This rule helps to the consumer to make an informed decision, rather then being subjected to subliminal-style manipulation that resulted in greater profits for tax-subsidized multinational factory food conglomerates.
This is about protecting the tax payer, clearly.