Why US media don't report when Syrian rebels kill children?

"At least 14 civilians, including seven children, were killed Sunday when rebels in Syria shelled a government-controlled neighborhood in the northern city of Aleppo, the government and an activist group said." "The rebel coalition, known as the Army of Conquest alliance, includes Syria's al-Qaida branch, the Nusra Front, and the extremist Jund al-Aqsa group, and is backed by Turkey and Saudi Arabia."