Du You didn't want to do such things. If someone provoked him, Du You would do everything possible to exact revenge. But if he wasn't provoked, Du You didn't like to senselessly kill the innocent; that was his principle.
If he didn't have principles, his mentality would have changed long ago, and Du You didn't want to become a psychopath.
Hence, although there were many missions in the academy to deal with others, such as the American Alliance and the European Alliance, Du You ignored them all. Engaging in such actions might be beneficial for the Asia Alliance, but they didn't align with his values.
With the level of power Du You had reached, no one dared to force him to do anything. The rewards didn't entice him; there was nothing to be done about it, and not even once had someone come to persuade him.