Who said 'The essential American soul is hard isolate stoic and a killer It has never yet melted' in the film 'Hostiles'?

The quote "The essential American soul is hard, isolate, stoic, and a killer. It has never yet melted" is said by the character Joseph Blocker, played by Christian Bale, in the film "Hostiles." This line reflects Blocker's cynical view of the American spirit and the harsh realities faced during the violent period in which the film is set. The film explores themes of violence, redemption, and the impact of historical conflicts.