The writer of the Psalm is mourning the complete destruction of their holiest temple and city, Jerusalem, and the mass slaughter of their people. In their rage and sorrow after the death and destruction they have suffered, they wish the same upon those who inflicted it. This includes razing the Babylon empire to the ground (as the Babylonians did to Jerusalem) and the killing of their children (as the Babylonians did to their children).
It is a tough read, as the writer is clearly in distress, but this action is seen as just punishment by the writer and a fulfillment of the Prophecy in Isaiah 13:16. In addition the action was unfortunately common in the times of the Old Testament, as shown in Homers Iliad. Let me know if you have any more questions.
I have the tendency to infer that the Bible is the bedrock of American Christianity. But your meme speaks truth. Nobody but me and like Mike Pence care what it says.
By the rivers of Babylon we sat and wept
when we remembered Zion.
There on the poplars
we hung our harps,
for there our captors asked us for songs,
our tormentors demanded songs of joy;
they said, “Sing us one of the songs of Zion!”
How can we sing the songs of the Lord
while in a foreign land?
If I forget you, Jerusalem,
may my right hand forget its skill.
May my tongue cling to the roof of my mouth
if I do not remember you,
if I do not consider Jerusalem
my highest joy.
Remember, Lord, what the Edomites did
on the day Jerusalem fell.
“Tear it down,” they cried,
“tear it down to its foundations!”
Daughter Babylon, doomed to destruction,
happy is the one who repays you
according to what you have done to us.
Happy is the one who seizes your infants
and dashes them against the rocks.
For context, the book of Psalms is a collection of jewish hymns. Psalm 137 is written from the viewpoint of defeated jews in Babylonian exile; the last verse may well be read as a defiant answer to the line "sing us one of the songs of zion!". The god of the bible is not speaking directly here nor is he being addressed.
As additional context, Boney M's disco version is actually a cover version of The Melodians "Rivers of Babylon" (featured on the soundtrack of the film The Harder They Come) and tactfully omits the verse about dashing Babylonian infants against rocks.
ESV - 16 Samaria shall bear her guilt, because she has rebelled against her God; they shall fall by the sword; their little ones shall be dashed in pieces, and their pregnant women ripped open.
Perfect example of "don't take the Bible literally" when you point out its contradictions. That article even points out a contradicting verse from Romans and says "use that one instead". So dumb. Maybe don't include that verse on psalms in the Bible if it's not meant to be followed. There needs to be a new council of Nicaea.