A 15-year-old boy was sentenced to life in prison for fatally stabbing a stranger, Muhammad Hassam Ali, after a brief conversation in Birmingham city center. The second boy, who stood by, was sentenced to five years in secure accommodation. Ali’s family expressed their grief, describing him as a budding engineer whose life was tragically cut short.
I readily concede the fact that a 15-year-old's frontal cortex is not completely developed.
I reject the idea that only a fully mature frontal cortex is capable of restraining someone from murdering a teenager. Even a radically undeveloped frontal cortex is more than capable.
This kid went out that day with a deadly weapon, seeking out the person or people who had previously attacked his friend, intending to commit violence against that individual. He found this teenager. Based on this teen's race, he believed this teen was complicit in his friend's attack. He spent 4 minutes arguing with this teenager, then stabbed him.
This wasn't a crime of passion. This was premeditated. He left his home that day intending to use his knife on someone. He knew his actions and intent were criminal and immoral, and he chose to act anyway.
Everything else in your last comment is an ad hominem, and doesn't need a response.