He didn't offer; he was merely pointing it out.

"To be fair, it's not so much destroying him these days as it is humiliating him and making him feel worthless. Which was working quite well, until we ended up here."

He doesn't say a word about the Doctor's insistence that it was 'nothing terribly upsetting'. But honestly. How long does he think he can get away with that? The Rani is all sorts of unflattering things, but 'stupid' has never been one of them.