If you think these thread are for downplaying Naruto, first you try to make him understand what he's asking. And if the OP is still biased and reluctant to understand, you are good to dislike his posts and neg rep him even, because that means he's only trying to force his opinion and not confused. But disliking the post right away is honestly beyond me.
Your assumption about the OP might be right, but the point is disliking an interrogative thread (for whatever purpose) right away is unreasonable. You can first encounter with the OP and make him understand, like it should go. Then after he dumps your opinion and is reluctant to understand, then you do whatever you like.
I never dislike or bash any such type of thread.