He's using an analogy to drive home a point about authority, persuasion and command. The principle might have been better applied elsewhere, but that doesn't mean there's no substance; ironically you haven't seen the substance (essence) because you became hung-up on appearance. The essence may be less profound than he lets on, if we divorce it from the psychoanalytical justification, which is the point that when someone is kind to you (or gives the appearance of being so), you will feel less inclined to disobey, but it is merely the use of the techniques of someone experienced in convincing.