n0mesorah,
“I’m using the ‘beliefs are irrelevant’ line, for the opposite extreme. When determining what is within the ‘norms’ of Frum Yidden, I think it is about observance. As beliefs alone does not make a Yid.”
That seems fallacious to me. Just because beliefs alone do not make a Yid does not mean that observance alone does so. Both are needed.
“So long as all the practice is being practiced, there is room for more extreme thought systems.”
We tend to accept those who are outwardly observant as “frum” and consider those who are not outwardly observant as “not yet frum” because, as human beings, we can only perceive the outside of another. Therefore, we use observance as a proxy. This is a human limitation, but you seem to be turning it into a personal philosophy. Also, Jewish history shows that we do indeed have machlokes based on thought systems rather than observance. Sometimes the new and different ideas become integrated into klal Yisroel, other times they result in groups R”L going off the derech.