I don't know; "absolutely" can add emphasis. Advising someone not to use it because "agree" covers it anyway feels like trying to suppress their personality. We're communicating, not playing language golf.
I feel that it dilutes the meaning of whatever comes after. "I agree" conveys a stronger tone than "I absolutely agree". Same as "I love you" is more powerful than "I absolutely love you". I see it as a filler word that doesn't add anything to the sentence. It's subjective I know. Also I would add that if you "absolutely [verb]" all the time you might as well [verb].
