They [his superiors] liked his diffidence when he apologized for the company he kept, his insincerity when he defended the vagaries of his subordinates, his flexibility when formulating new commitments. Nor did he let go of the advantages of a cloak and dagger man malgré lui, wearing the cloak for his master and preserving the dagger for his servants.
Source: Call for the Dead by John Le Carre
I understand that malgré lui means "in spite of oneself" but am having difficulty understanding it in this context. He did not let go of the benefits of being mysterious (cloak and dagger?) in spite of himself?
Does the last part ("wearing the cloak...preserving the dagger") refer to his duality in dealing with his superiors and subordinates respectively?
Does "Preserving the dagger" refer to his willingness to backstab his underlings whenever he can?
And why do his superiors like his insincerity, diffidence, and flexibility?