It is because of the love and tenderness* they bear towards (Rāma), that people do good to each other. *The commentator explains in pure orthodox fashion: Because every-thing is in Rama, people serve each other from the love and tenderness, which partain to him.
अन्योन्यमुपकुर्वन्ति स्नेहकारुण्ययन्त्रिताः। ततस्तस्योपकारार्थं त्यजतात्मानमात्मना ॥