A comment from one of my readers:

When you are asked, "How are you" it is indeed correct to
reply, "I am good," not because you are saying that you are
morally good, but because "am" is a linking verb, and with
linking verbs, the adjective is preferred over the adverb.
That's how I understand it, at least. "Well" is used in
reference to health. 

The debate continues . . .