If one responds kindly to a person who shows him/her kindness, then where is the saintly quality in this? There simply is none.
But when one responds compassionately/empathetically towards one who shows enmity towards him, curses him and causes him/her pain, then this is seen as the beginning of saintliness by the wise.

When I take a step back to think that any response a person may have is due to a background and they are helpless to respond and only will respond in the way that they can, according to their background and if I was them, having their background I would say and do the same things. With this understanding how could I be anything but non-judgmental, empathetic and acting on my empathy towards the person.