He doesn't want to hurt or infect anyone, but he has to, he has someone depending on him that he has to save and to him working for Deoxys is the only way to do it. You see he is an axew and lived in the wild with other Axews and Haxoros etc. when Deoxys and his infected came to his village everyone was killed due to lack of cooperation and attacking leaders immediately after infection, Sho somehow managed to defeat one of Deoxys generals and was given the chance to live if he agreed to infection fully and wholly, he refused, but then changed his mind when Deoxys showed him that they had taken his sister hostage and would kill her aswell if he refused. So Sho agreed and became a stage one infected :3