Menachem, i never said that the realization that chabad isn’t the end all be all, or that the lubavitcher rebbe had many detractors is the sole or even the most common reason for going off the derech – i don’t think it is. What I’m saying is that unlike a litvishe person whose yiddishkeit isn’t concerned with the fact that there were big machloksim between the satmar rov and rav moshe, a lubavitcher can have a crisis of faith over such things, due to the unparalleled emphasis of a rebbe not found in any other chasidus.
And I’ve seen it happen. I’ve also read about it in my days on frumteens, when lubavitcher teenagers would write to rabbi shapiro and ask him to stop writing against chabad, because they knew many people who were going off because of his articles, which at the time were almost the only place online where you could find the yeshiva world’s perspective on lubavitch. And even now, very few online outlets serve as open forums for the issue.