AviraDeara,
You’re not just ignorant; you’re misinformed. To say that the Chabad Rebbes and their hundreds of thousands of Chassidim did not sleep in the Sukka due to the Russian cold is just preposterous.
Don’t you know the Miteler Rebbe’s popular saying “Vi ken ich shlufen in makiffim d’bina – How can I sleep in the lofty spiritual levels of Makifim D’bina?”. And don’t you know that this was the reason that the Chabad Rebbes and their respective Chassidim all refrained from sleeping in the sukkah, all to to the complete silence of every Gadol around at the time? Have you bothered, at least once, to read up on the subject in Chabad texts or asked about it from Chabadniks before concocting your own narrative?
It would certainly due you well to watch the dialogue between the Rebbe and R’ Tzvi Kahana during Sunday dollars, available to view on RebbeDrive or Youtube, where the Rebbe effectively removes all doubt on the matter. This is Chabad’s (and Belz’s) established minhag. It’s been around since the early 1800s. Not ONE gadol (until Rav Shach, of course) got up to say a word about it. NOBODY, not even CR participants, can contest this sacred minhag, and if they do, they should know that they’re contesting the Mitteler Rebbe, Tzemach Tzedek, Maharash, Rashab, Rayatz, the Rebbe, who all refrained from eating in the sukkah, and instructed their chassidim to do likewise, not because of weather considerations (!), but due to their holy kabbalistic intentions backed up with the proper halachic support presented at great length in Likkutei Sichos and other sources.