“How blessed will be the one who seizes and dashes your little ones against the rock,”
If you look at the written scripture in context you will see that the Bible does not say it is okay the kill babies. The Psalmist was speaking of the Babylonian captivity, and how the captors were treating God’s people. Revenge was very common in those days and the Psalmist wished the same to the captors as he may have witnessed those offences done to them. He wanted their complete annihilation.
There is no scripture that reads that God condoned such actions. It was merely recorded in the Old Testament.
The atheist or skeptic in any case must first have a standard against which to measure good and bad, to say this is unacceptable; and without a standard, no complaints can be legitimately offered. This is a sincere question that if not answered by the skeptic, makes the critics’ accusation problematic.