It appears that they're attempting to apply Socrate's quote, "When the debate is lost, slander becomes the tool of the loser", to invalidate your argument, but they are failing to realize that "devoid of common sense" is not an insult or slander, much like those that fail to realize the same about being called ignorant when they argue out of ignorance.
My point is that whether a belief is popular, or whether you think a belief is common sensical has no bearing on the truth value, social value, rationality, or perspicacity of that belief. I don't think the GP is slandering the GGP, I think they are both missing the point and making an irrelevant quasi-argument.
