Beans and Beanstalks - Brothers

“煮豆燃豆萁，豆在釜中泣。本是同根生，相煎何太急。”

With beanstalks burning under the pot, the beans are boiled and weeping in the pot.

Originally grow from the same root, why do they torture each other so hard? The beans that are burned and cooked are the beans that grow from the same root as themselves.