Thank you for writing a balanced perspective. I share your viewpoint that food, grown locally, is both sustainable, good for local economy, and planet friendly. However, wherever possible, a plant-based food lifestyle is healthier in the long run for both the planet, other plants, animals, insects, birds, water life, and humans. For that to happen, eating in moderation (even meat for that matter), growing food on your own, eating in season, grow, share, exchange, and buy food locally are the only way forward.
Then again, as you may argue, if everyone were to rely only on local resources, what would happen to the global supply chain? Would that collapse? What would be the cost of that collapse? Who would gain and who would suffer?
In the end, we are all inter-dependent, we are part of a giant hive of the world where every human being, every animal, plant are inter-dependent on each other in every which way. There is nothing black and white, nothing absolute. However, the point is to choose wisely so that we inflict least harm to the world around us.