Good for you is an expression, it does not tantamount to approval. Usually used when other person is unnecessary bragging about himself and you politely wants to end the conversation saying good for you meaning I agree with you, it is good you are doing that and it is good for you. I on the other hand does not give a damn about what you are doing. I am happy for you now lets get back to the topic.
I did not ask for clarity either, unsolicited as it was, but ok.
Cheers, Doc