It is important not to allow ourselves to be put off by the magnitude of others' suffering. The misery of millions is not a cause for pity. Rather it is a cause for compassion.
Great Powers of falling wave and wind and windy fire,
With your harmonious choir
Encircle her I love and sing her into peace,
That my old care may cease.
If indeed the qualities such as love, patience, tolerance, and forgiveness are what happiness consists in, and if it is also true that compassion, defined as concern for others, is both the source and the fruit of these qualities, then the more we are compassionate, the more we provide for our own happiness.
Contemplating the suffering which is unbearable to us, and is unbearable to others, too, can produce awake mind, which arises from the compassion that wishes to free all living beings from suffering.
Apart from selfish reasons, such as fear of punishments, fear of blame, of dishonour, etc, there remains only two motives that can stop (or prevent, "empâecher", Fr.) men from acting badly; the natural sense of commiseration (or "sympathy", - "commisération", Fr.) for one's fellow men - compassion, and the influence of education, by association of ideas ("par l'association d'idées", Fr.) - habit.
If pity was always equally alive and acting in all individuals and in all circumstances, we could do away with moral. Unfortunately, it is not compassion, but rather it's contrary, selfishness, that act most strongly in us.
Humanity is not without answers or solutions regarding how to liberate itself from scenarios that invariably end with mass exterminations. Tools such as compassion, trust, empathy, love, and ethical discernment are already in our possession. The next sensible step would be to use them.
Be guided, only by the healer of the sick, the raiser of the dead, the friend of all who were afflicted and forlorn, the patient Master who shed tears of compassion for our infirmities. We cannot but be right if we put all the rest away, and do everything in remembrance of Him. There is no vengeance and no infliction of suffering in His life, I am sure. There can be no confusion in following Him, and seeking for no other footsteps, I am certain!