@Acolytus Because he is a minor and he was unarmed. Outside of violently beating other cops, he didn't kill anyone so they would want to subdue him by force. If he was holding a weapon, it would be different. Unless you counted that potato he was holding as weapon, JK.
Even here in the US, police is not allow to shoot an unarmed suspect. As a true crime and law enthusiast, I know that if a police officer shoot an unarmed suspect, he/she will be suspended and got investigated by Internal Affair and DA office, depend on the situation, he/she can be charged with homicide.