If I buy a bunch of seeds, plant them, grow a bunch of vegetables, and sell the vegetables for more than the price I paid for everything (seeds, fertilizer, tool wear and tear, and any other expenses related to the garden), I have made a profit. It doesn’t come at the expense of anyone.

It wouldn’t be fair to insist I sell the vegetables at exactly the cost of everything I put into them. I put my own labour into growing them and bringing them to market. If I couldn’t profit by selling them then I wouldn’t sell them, I’d just eat them myself or not even bother growing them at all.