What is the significance of the phrase "Happy is the one who seizes your infants and dashes them against the rocks" in Psalms 137 verse 9?

The phrase "Happy is the one who seizes your infants and dashes them against the rocks" in Psalms 137 verse 9 reflects the intense emotions of anger and vengeance felt by the Israelites towards their enemies. It highlights the brutality and desire for revenge in times of conflict and suffering.