AlwaysAsk to Avirah: “You are suggesting that gedolim were making judgments about major current movements lead by other gedolim without investigating the matter properly?”
Not quite. Avirah is suggesting that they made judgments after investigating the matter as far as they could. Don’t forget that Lubavich are experts and believe in propaganda, as the Lubavicher rebbe himself said חזקה לתעמולה שאינה חוזרת ריקם. So many gedolei Yisrael believed that the views and situation in Lubavich were not what they really were.
What I have written is not radical or surprising. There were many gedolei Yisrael who believed that Shabsai Tzvi (NO! I’m not comparing c”v.) was a great tzaddik and possibly Mashiach until the full facts came to light. אין לדיין אלא מה שעיניו רואות.