True, but (not defending Epstein) children are charged as adults for crimes starting at about 12/13. Meaning that judges and courts say they are in fact capable of knowing the implications of their actions. Age of consent goes from 12 and up depending on countries and cultures as well. "Children" being a subjective term it is a slippery slope.

Some adults lack the capacity to make adult decisions as well, but since they are over 18 they are free to do so.

Point being, it's rather subjective. The girls were manipulated and in a power structure that made it very difficult to break away. That is the real crime.