Do you understand the context of that verse from Psalm 137?
It is about the Jewish captivity in Babylon -- the Babylonians who had dashed the heads of the children of the Jews against the rocks, were now demanding the Jews sung for them a song of their lost homeland,
Here is the whole Psalm:
By the rivers of Babylon, there we sat down, yea, we wept, when we remembered Zion.
We hanged our harps upon the willows in the midst thereof.
For there they that carried us away captive required of us a song; and they that wasted us required of us mirth, saying, Sing us one of the songs of Zion.
How shall we sing the Lord's song in a strange land?
If I forget thee, O Jerusalem, let my right hand forget her cunning.
If I do not remember thee, let my tongue cleave to the roof of my mouth; if I prefer not Jerusalem above my chief joy.
Remember, O Lord, the children of Edom in the day of Jerusalem; who said, Raze it, raze it, even to the foundation thereof.
O daughter of Babylon, who art to be destroyed; happy shall he be, that rewardeth thee as thou hast served us.
Happy shall he be, that taketh and dasheth thy little ones against the stones.
This is not to justify the violence in the Old Testament, but to put into context the passage you mention here. The Quran certainly does contain passages ordering abuse and torture of enemies -- using captured women as sex slaves and so on -- but also to be taken in context, of course