your interior voice of self-criticism doesn't know anything you don't know, which means it can't provide any new information that's more correct than what you already have.
and I want you to remember that, when he* comes through to cut you back down to size and remind you of your real worth, your place in the world: he will take the tone of correcting you for your own improvement, but how can he be right and you wrong if he has no information you don't have? how could he have the advantage over you if he's working from the same information you are?
he doesn't know anything you don't know, he can't teach you anything. he just hates you, he's just taking a high-handed approach to make you feel bad because that's what you're used to from authority figures in your life. you can tell him I told him to piss up a rope, if you want.
* could be a she, but usually I've heard that the voice is a he
