Why would Ender view adults as enemies?

The adults in the story, Graff, Pace, Rackham, continuously push Ender and manipulate him to their own ends. People tend to forget that Ender is only six years old. For adults to consciously prod and even promote violence is an atrocity. These men set Ender up, put him is dangerous, and purposely lie to him to him throughout the story. Ender is young, but he's not foolish. He can sense there's something, although, he cannot always put his finger on it. Graff proves himself an enemy by befriending Ender and setting him above the others..... only to allow him to be hurt. Rackham doesn't waste his time, he tells Ender he's an enemy from the start.