Orwell could not comprehend that, regardless of the specific flavor of socialism —whether Trotskyist, Stalinist, or otherwise—given enough time, it would inevitably lead to the same outcome: economic stagnation, moral decadence, and repression. His deep belief in the potential of socialism, particularly in its democratic form, blinded him to the inherent authoritarian tendencies within socialist movements.
This is not surprising in respect to both his seminal works. After all, he was, first, last and always a socialist.