peasant illusion

Engels has said: “As I see it, we can perfectly well enter the arena on behalf of the oppressed fellaheen without sharing their current illusions (for a peasant population has to be fleeced for centuries before it learns from experience), and against the brutality of the English without, for all that, espousing the cause of those who are currently their military opponents." What does he mean by "current illusions"? And it "learns" what "from experience"?