This question is certainly not a simple one to respond to because it is evident that the presentation of the gang and its members is not simply a caricature of delinquent youth. Greene is in fact very careful to explain their motives and especially those of T. by referring to the post-war conditions of life that they have grown up in. These children are literally children of the war in that they have grown up surrounded by the debris of the London Blitz and in many ways they are victims of the social upheaval caused by the war and the class system. It is also clear that T. and the gang destroy Old Misery's house through no motive of hatred or revenge - think of how they care for Old Misery during his night of captivity in the outside bathroom and also how T. neither loves nor hates. However, images abound of hollowness and rotting from within, which perhaps suggests that human nature needs an appropriate context and setting with which to flourish. Given the bleakness of the setting, Greene is clearly pointing towards the moral malaise that has occurred and its impact on the youth who had never known a reality other than war and its aftermath. Thus, respectfully, I think this story paints no clear message of human nature, but instead looks at the impact on human nature if certain key essentials (such as peace and stability) are removed from the upbringing of children's lives.