I did some research, and here is what I found out about the disturbing psalms.
Imprecatory psalms are those those psalms that contain curses or prayers for the punishment of the psalmist’s enemies. To imprecate means to invoke evil upon, or curse. Psalms 7, 35, 55, 58, 59, 69, 79, 109, 137 and 139 all contain prayers for God’s judgment on the psalmist’s enemies. Example imprecatory statements from the Psalms follow:
• Psalm 55:15 - Let death take my enemies by surprise; let them go down alive to the grave.
• Psalm 58:6 - O God, break the teeth in their mouths.
• Psalm 69:28 - May they be blotted out of the book of life and not be listed with the righteous.
• Psalm 109:9 - May his children be fatherless and his wife a widow.
• Psalm 137:9 - How blessed will be the one who seizes your infants and dashes them against the rocks.
“While these psalms are not positive and pious, they are honest expressions of pain in the face of grief and endings. We should not attempt to Christianize them by pretending they are something they are not. Yet neither can we exclude them as sub-Christian. Rather we need to take them seiously as a valid biblical response to God in paryer from the depths of our humanity. Since we accept these psalms as scripture for th church, we need to allow them to inform our theology rather thatn using our theology to change the psalms.” From “INTRODUCING THE PSALMS” by Dennis Bractcher.