Chazon Ish: Lashon harah about gedolim is required - if there is to'eles

I was recently told that it is prohibited to say anything negative about a talmid chachom - even if true. Obviously my critic disagrees with the Chazon Ish

Rabbi Alfred Cohen - “Privacy – Halacha and Contemporary Society April 1981 page 68). It is told about Rabbi A. I. Karelitz, known as Chazon Ish (1878-1953). that he loved to reminisce about "gedolim" (outstanding Torah scholars and leaders). and incidents in which they played a role. Now, the Chazon Ish was well-known as a person who had spent decades closeted in his study, filling every minute of every day for years, engrossed solely in learning Torah. How then, could he waste his time in idle chitchat about other Rabbis? But he explained that we learn not only from the formal legal opinions published by brilliant Talmudists, but equally from their casual conversations and from their reactions to ordinary human occurrences. And if sometimes even a revered leader fell short of the ideal in his actions, the Chazon Ish did not hesitate to relate that as well - so that the masses would not blindly follow. (Interestingly, however, one time a visitor launched into a story about a certain public official, and the Chazon Ish held up his hand to stop him. "No, no," he admonished, "that person is by no means a Gadol, and to talk about him is certainly not allowed; it is only gossip."[ 15. This is a personal experience ot the Chazon-lsh’s grandnephew, as related to this writer. The Chazon lsh in one of his letters (2:133) notes that once his Shabbat was disturbed since he feared he had spoken evil against a scholar, but assures the reader that it had to be said for one is obliged to know the ways of scholars. However, he admonishes his audience not to add on even an extra word lest he be speaking evil talk against a Torah scholar. ]

Chazon Ish(2:133):Knowledge about a talmid chachom who shapes yiddishkeit is similar to that of an artisan. Just as one is permitted to convey accurate information about an artisan if there is to'eles so it it permitted to reveal information about a gadol if there is to'eles. Of critical importance is to be totally accurate otherwise it is slander. This implies that expressing negative information about others is relevant for those who are considered influential authorities – in order to understand the degree to rely on them.