Why Would Iraqis Kill Children?

A car bomb went off outside a Kirkut bus station killing seven, and wounding twenty five. The bomb was so massive that 25 shops and 10 cars were destroyed, and the toll was ordinary Iraq families.  Kirkuk, a volatile city claimed by both Kurds and Arabs that has witnessed regular bomb attacks and shootings.
 
Kirkuk, which sits on Iraq's northern oil fields, is shared by Kurds, Turkmen, Shi'ite and Sunni Arabs. The Kurds want their own country, Kurdistan, which sits on massive oil fields.