Why does Göth shoot the boy? Was it because he did not understand what Schindler meant? Or because he would rather kill? How did Oskar think? I am so thankful for answer! Please if possible write more details so it will be more descriptive

I think that Göth just doesn't like Oskar's concept of power and letting people live. Göth is a twisted soul and feels the need to indiscriminately kill people. He shoots the boy because he can shoot him. I don't think Oskar would have been happy with the shooting of the boy. Göth is full of hate contempt. He kills but feels empty.