was all the pressure put on Ender justifiable (necessary)??

It is difficult to remember that Ender is only six years old. It would be seemingly impossible for a six year old, even a gifted one, to perform the complex military tasks that Ender pulls off. Assuming that Ender was intellectually up to the challenge he was still emotionally still a child. Consider how Ender dealt with his anger and frustration through the novel. Ender is obsessed with beating the Giant's game. He develops an unhealthy need to beat it. Ender also kills Bonzo when they met in the shower. Ender was still trying to reconcile his pressure with his emotional capabilities.