"Korean is like that."
Use 저 when talking about "that" which is far from both the speaker and listener.
Use 그 either when talking about something far from the speaker and close to the listener or when talking about "that" which is being talked about.
Is 저래요 the default if not referring to something close to the listener? Because in this sentence it refers to Korean which is not an object that can be close or far from someone.
I also do not understand what you mean by "when talking about 'that' which is being talked about." Just trying to understand, thanks for explaining!