What does Catholicism teach about 'The Massacre of the Innocents'? Matthew 2:16 says:


  When Herod realized that he had been outwitted by the Magi, he was furious, and he gave orders to kill all the boys in Bethlehem and its vicinity who were two years old and under, in accordance with the time he had learned from the Magi.


Wikipedia says that "[The Massacre of the Innocents] is understood as the fulfillment of an Old Testament prophecy. And while I can appreciate that this event is inextricably linked to Jesus' birth, I feel like it has its own significance.



My Question:  


How are Catholics taught to respond if they observe infanticide, genocide, or a mass killing in their own lives, when it appears like the event might be fulfillment of prophecy?
Are they taught to simply mourn the dead? Or are they taught to organize and respond in some way?
From the Daily Roman Missal, According to the Roman Missal, Third Edition


  THE HOLY INNOCENTS, MARTYRS, Feast, December 28
  
  This feast celebrates the memory of the male children King Herod ordered to be killed in his attempt to kill the infant Christ. These
  innocent victims thus bear witness to Christ in the world and God's
  care for even the most helpless of people


The bold is therefore the Church's Teaching.


  Continuing to the ENTRANCE ANTIPHON
  
  The innocents were slaughtered as infants for Christ; spotless, they follow the Lamb and sing for ever: Glory to you, O LORD.


Their reward for dying for Christ. [Most likely for their mothers too]

How are Catholics taught to respond if they observe infanticide, genocide, or a mass killing in their own lives, when it appears like the event might be fulfillment of prophecy? Are they taught to simply mourn the dead? Or are they taught to organize and respond in some way?

[My thoughts:] Prayer then action are an appropriate Catholic/Christian response. Prayer for God's care and justice for the victims, and prayer for mercy and forgiveness for the perpetrators. Action: do all one can to mitigate what is coming [save as many as one can; the Holy Family escaped to Egypt] and christian charity after it happens.