They have no remorse because a child brain is still a developing brain and the connection between right wrong black white are morphing into shades of grey.
A child doesn't deal with things the same as an adult because they aren't mature enough to fully understand consequences.
Its why they don't vote, drive, join the military, hold jobs, be responsible for their own education etc etc. They re still learning and developing and its physiological. To write somebody off at 12 is just wrong. Not saying they will ever be decent citizens however their lives are much surer to be a constant drain if you ensconce them with adult laws and conventions