I think what “khmer” meant to say was that the U.S. military & the U.S. State Departments initial classified B-52 air bombings over the Cambodia countryside was used by the Khmer Rouge leadership as an excuse to recruit and cultivate anti-American sentiments. Most of the Cambodians in the countryside, especially farmers were not very educated about the conflict that was spilling across the border from South Vietnam, American intentions and the growing ranks of the Khmer Rouge. Much of the bombings indeed killed many Cambodian civilians (~100,000). Some were even miscalculated and towns & villages were annhiliated (i.e. Neak Lung). Much of this in addition to the mix of Khmer Rouge propaganda helped recruit many farmers and uneducated people into joining the communist movement. Without the U.S. bombings, the Khmer Rouge movement might not have gained as much momentum as it did during the early 1970′s. But I do agree with you, at the end it was Cambodians slaughtering their own people.