Melbourne; it’s the definition of mitztayer that I’m not going to accept – it’s not something we find in halacha in other places. For instance, one can take medication on shabbos if they are in pain – it doesn’t say you can take medication if you are in pain because you’re not in pain. I know the comparison is a bit off; maybe someone else here can think of a better one, but the main issue is that we don’t find the idea of being mitztayer that you’re not mitztayer being an inyan, nor do we find that ruchnius issues like that are applicable in halacha especially regarding a deoraysoh.
Re, the rema – that’s exactly how i answered the statements attributed to the miteler rebbe. He had a normative halachik heter that he and many other rabonim used. That heter is in the rema regarding men who are unable to be there with their wives – the rema rejected the cold heter, but many other poskim accepted it.
However the only people ever to not sleep in a sukkah in eretz yisroel are neo-chabad. It’s not minhag hamakom and it’s a big pirtzas geder, since literally everyone sleeps in a sukkah there; chasidim, litvishe, sefardi…even religious zionists; everyone. Until this idea of being mitztayer that you’re not mitztayer was matir lubavitcher chasidim who live in eretz yisroel to go against an extremely established minhag.
Even if, theoretically, there would be a heter in eretz yisroel (where it’s not cold) it would not license people to be poretz geder. This was one of rav shach’s main issues in his opposition.