The distinction between good and bad is not to say that one tree is morally superior to another. In God’s creation there is a place for vines and thornbushes, for fig trees and thistles. Trees are morally neutral. Jesus’ emphasis is on the fact that different trees produce different fruit. You do not look for grapes on thornbushes, and you do not look for figs on thistles.
17 So, every healthy tree bears good fruit, but the diseased tree bears bad fruit.