If young boys had nothing to do with a treaty should they be beheaded?

muslim book 38 # 4390 narrated atiyyah al-quaazi; i was among the captives of the ban quratzah. they, the companions of the apostle examined us, and those who had begun to grow hair [pubic hair] were beheaded, . i was among those who had not grown hair;; now! mohammad had a trench dug in medina and beheaded between 700 to 900 men and boys after they surrendered. so how many agree it was wrong to murder these boys if they had nothing to do with writting a treaty or breaking it?