There is nothing about fighting a counter-guerrilla war that makes it necessary to kill civilians; in fact, and more so than in a conventional war, such incidents are very much strategically damaging.
However, it was official US policy, according to Henry Stimson, to engage in terror bombing in WWII. Moreover, it was official US policy (as stated by Commanding Generals at each time) to make civilians suffer, by attacking facilities and electrical grids, in the 1991 Gulf War, in 1999 in Belgrade, and in 2003 in Iraq; these policies led to high-death tolls of infants and the elderly, those whose lives most relied on water, sanitation, and electricity. These are not attacks intended against militants where by the doctrine of double-effect civilians are harmed; these are attacks where civilian suffering is the intent. It is terror-bombing.