This cartoon from The Seattle Times illustrates how America's economic pizza is actually sliced per capita, highlighting the massive disparity between the Top 1%, the merely wealthy, the upper middle class, and the lower 50%.
Where do the ingredients come from? Are you growing your own grain and milling it into your own flower? Do you have your own cows or goats to make your own cheese? Did you build your own oven? Fired with wood you cut down yourself?
Not buying the very last link in the chain doesn't matter. It only makes you feel like you're doing something.
You'd be more effective buying the pizza from a locally owned place.