Quran 9:5 – Itmam-e-Hujjah And Children
What you’re referring to as nuances are not random. Itmam-e-hujjah takes place in stages. Depending upon the behavior of a given nation not all stages would be rendered or even necessary. Prophet Jesus’s addressees were in reality believers of monotheism, and the law itself has different a treatment for such people. Itmam-e-hujjah or culmination of proof has to do with people who are able minded. It doesn’t apply to children. As Ghamidi sahab stated and is evident from history that children were also killed, so there’s no basis for the assumption that they were spared. This is quite comprehensible as a result of an azab, and the same applied to the previous nations who knowingly denied the truth as well. When we understand this life in context then I don’t think that there’s any room left for objections. We existed before we were sent to earth, and we shall continue to exist even after we die. Our life in this world is just a temporary phase, and it’s entirely up to God that how long this phase lasts for each individual. We know that on the day of judgement no injustice shall be rendered to anyone, whether a child or an adult. Such children who did not have a chance to take the test of this life will most certainly not be held accountable for their actions.
What about the basis in the Quran 9:6?