There's no merit in discussing with Dennis. As long as you're in agreement with him it's fine, but discussions with diverting opinions are absolutely pointless with him.
gturner might be wrong, and you might disagree with his posts, or even find them laughable, but he is still trying to make his point.
Dennis, as soon as he runs out of arguments, or gets bored, just declares himself the king of the discussion by posting his absolute "No.", as in "You're wrong and/or stupid, and I don't even care to explain why." That makes him feel better about himself, I guess, as he thinks this behaviour somehow elevates him above the average internet nerd he always speaks so fond of. Discussing with people he strongly disagrees with is just below him. But at the end of the day, he simply loses the argument every time he does it.
He could say nothing at all, but instead he uses the "No." in an attempt to get the last word, no matter how pointless it is. You could replace it with "Balls." or a fart noise, and it would have the same childish effect.
He also occasionally uses the condescending "kid", just to establish a hierarchy in the discussion where he's the know-it-all and you're the child that can learn from his wisdom.
Last thing I'm ever going to say about this specific matter.