Insult and criticize the previous comment in a very aggressive and derogatory manner, and suggest that it lacks intelligence and thought.
Blunt, I will be blunt.  I know you are a nice person, but your comment is stupid, ignorant, dense, brainless, mindless, dull witted, feebleminded, simpleminded, vacuous, obtuse, vapid, irrational, idiotic, knuckleheaded, bubbleheaded, lunkheaded, dim, dumb, dopy, half-witted, childish and just plain nuts.  I apologize if I missed something.