It's a bit tart but it isn't actually saying "We know better than you. Shut up and do what you're told."

What it is saying is that if you don't want to be a part of a community then that community has every right to make decisions without you. You can want to stroll in once a week to the Mega-Mart on a 45-mph six-lane road through the center of town, and the people who live in the town can want to walk safely, breathe clean air, and live close enough together to foster a sense of community with their neighbors.

You're free to live in the sticks but when it comes down to it you are a visitor who isn't invested in the wellbeing of the community and that should be reflected in how much political capital you wield there.

It is absolutely saying "we know better than you". It's comparing a differing preference to contaminating shared food. It's attempting to paint that opinion, which actually happens to be the most common one, as despicable and able to be dismissed out of hand. This is an extremely common rhetorical technique with paternalistic types.

For what it's worth, I don't disagree with your point about outsiders needing to accept that they don't have influence within a community. I actually very much agree, but I don't think that's actually the point being argued, nor is it what I was taking exception to.

Fair enough, at the very least its not a very productive way to make the point regardless of the intent.