Hi, For some reasons that I cannot get to your link. Anyway, without being able to review that, I can only offer what it means in general. People use the statement ‘that’ll learn (somebody)’ to state a disapproval of someone’s behavior / to express an anger at someone for the behavior that brought about negative consequences - even after a warning had been given.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.