Upon re-reading R. Yehuda Levi's subtle condemnation of the Slifkin ban in the Jan/Feb 2006 issue of The Jewish Observer (pp. 50-51; here - PDF), I realized that he quoted a letter of the Chazon Ish that corresponds neatly to R. Aharon Lichtenstein's evaluation in this post. From Chazon Ish (Yoreh De'ah 150), as translated by R. Levi:
It seems that the rule "in Torah matters [in contrast to Rabbinic decrees] follow the more stringent opinion" applies only when none of [the ruling sages] is his rabbi, but if one of the authorities is his rabbi, follow him even [if he is] lenient. And he is called his rabbi if he is close to him and constantly studies his teachings in most commandments.... And this applies both during this authority's lifetime and after his demise, as long as his decisions and instructions are known from his disciples or his books. They may follow their rabbi even [if he is] lenient in Torah matters -- even if the majority disagrees with him, as long as there was no court session, with the authorities discussing the matter face-to-face, deciding the halacha.It is worth noting, to get an idea of the sensitivity of the readers for which the editors of The Jewish Observer have to account, the following "clarification" of R. Levi's article in the current issue (p. 21):
K'vod HaTorah has always been uppermost on the agenda of Agudath Israel. One may say that it is its raison d'etre. As its official publication, The Jewish Observer is certainly committed to this goal. The article "Halachic Decisions" (JO, Jan.-Feb. '06) called for more tolerance and understanding between groups that have honest disagreements in halacha, ideology or communal practices. Differences of opinion do not justify harsh criticism or violent expression. Some reader interpreted it to imply a dismissive attitude toward Gedolei Yisroel. This was certainly not the intention of the author nor of the magazine, and we truly regret that any such inferences were made.