Metta cannot co-exist with such unwholesome attitudes. Disparaging, condemning and belittling others is possible only through ill-will. Parents, teachers and elders often have to resort to various methods of correction and reform where the young are concerned. But one has to be very watchful when one is engaged in such activity. The motive has to be analyzed carefully.
Elders sometimes react in anger.
The son departed and the mother radiating metta towards her son, hoped and prayed that no harm should befall him. Though the jungle was infested with wild animals, the loving-kindness which radiated from the core of the mother's heart towards her son was a weapon against the fierce jungle beasts. Metta is a constructive healthy force with the power of combating hostile influences. Just as anger can produce toxic effects on the system, benign thoughts can produce soothing health-bringing physical effects. Many instances in the Buddha's life illustrate the fact that the peaceful thought vibrations of the Buddha produced salutary effects, so much so that the intoxicated elephant Nalagiri and the wild Angulimala were completely subdued.