MdLevine, I reread the article, and found the phrases you mention which were indeed a bit stronger than I remembered the tone to be, but still totally disagree with you. Rav Belsky initiated an attack on Chabad saying they deify the Rebbe. A representative of Chabad with kids in their schools responds by saying that he has never encountered such a thing in any Chabad institution. If that is true, he has every right to say that it is sheker, and by implication, motzee shem ra. I am totally confused why you think a person has no right to defend himself or his movement against an accusation that he believes is totally false. Especially, since the movement was headed by someone who was at least as big a godol as Rav Belsky.
If Rav Belsky accused you of stealing a thousand dollars from your shul, I guarantee you would use the same words in your defense. “I never did such a thing, the evidence is totally false, whoever told you that is being motzee shem ra on me, etc. etc. etc.” And you would have every right to do so.
I can see your point about what is the proper venue for his complaint, but Rav Belsky made a public accusation, and therefore the writer felt a need for a public defense. Why he chose YW instead of the original publication I don’t know, and possibly he should have and maybe did try to contact Rav Belsky directly. Nevertheless, a public accusation certainly invites a public defense.