Why is positively reinforcing the wanted behavior and ignoring the unwanted behavior considered an effective method of differential reinforcement?

It encourages the wanted behavior while not reinforcing the unwanted behavior

Positively reinforcing the wanted behavior and ignoring the unwanted behavior is considered effective because it focuses on strengthening the desired behavior by providing rewards or positive consequences while not giving attention or reinforcement to the unwanted behavior. This approach can lead to an increase in the desired behavior and a decrease in the unwanted behavior over time.