“Yet no one took issue if he didn’t sleep in sukka or had cake before davening.”
If he ate cake before davening, he was over an issur. If he didn’t sleep in the sukkah when he could have, he was mevatel a mitzvah. Need to hear me say it again?
Obviously, everyone was against these practices if he held of them. Silence does not imply approval. And, I don’t think you want to say it does, because then how would you explain the Rebbe’s “silence” on meshichism?