You can find ethical concerns with anything if you look hard enough. Supermarket foods are not on my list of things I get too wound up about. Yes, the farming practices of developing economies are not congruent with what we in our place of economic dominance and comfort expect, but that's part of "developing." Look at our own, or any first-world country's history.

Feel free to go to the Farmers Market on Saturday and pick up an $8 head of lettuce and some $4/ea heirloom tomatoes if it bothers you.