Hello, I'm Jeong Wonguk -(willie)
Yuri is just an arm trader. The first time, he just wants to earn a money without meditation of death and war. However, with time he realizes the disastrous reality. He witnessed the murder and people's pain. He rationalized his act. "Although I stop to sell a arms, other arm trader will fill his role." Moreover, He rationalized himself "I just sell a weapon, not death." Otherwise, His brother, Vitaly seems to have a bad conscience. He acts what he can do, even if that act is useless.
The last scene of this movie, Yuri was released by a General who has many medals. That scene implies that the government allows the arm trade. The reason why government allows the arms is economic advantage. The politicians receive a bribe and commission from arm trader and munitions companies. Moreover, they lobby the pressure.