Contemplating the various theological debates of the last few years, the following thought has repeatedly occurred to me. When those on my right insist that it is unacceptable to believe X (where X is anything from the world being millions of years old to Chazal being mistaken to the flood not being global to Torah not being divine to there not being a God), what do they believe the result of that to be?
It seems pretty clear to me that in many or even most cases you can't threaten someone into believing something. Much as those grappling with challenges may want to be a good Jew, they are not likely to suddenly start believing X because you tell them that one has to believe X in order to be a kosher Jew, especially if they are much more knowledgeable than you about the matter under question. If someone has a strong education in biology and has concluded that evolution is true, he is not going to stop believing that because a rabbi tells him that it is incompatible with Judaism. What will happen instead is that they will be deeply tormented and will either (a) reject the rabbi as a representative of Judaism, (b) conclude that Torah must be false, or (c) feel that they are bad Jews and eventually detach themselves from the religious community.
Now, in some cases this may be unavoidable. I simply don't see how it's possible to, for example, grant the legitimacy of someone denying the existence of God, or denying Torah min haShamayim in some significant sense, without fundamentally compromising Judaism. (Although if someone has such beliefs, it can still be possible to help them be part of the Orthodox community, if they so desire.)
But in other cases, is this what those to my right really want? That someone should feel that Judaism is not for them? Is it really so terrible if they say, "Look, I don't believe that evolution is true, and in my view it is really contrary to Torah belief, but I must let you know that there are plenty of Orthodox rabbis who believe otherwise"? Is that really worse than the alternative?
Rav Aryeh Carmell ztz"l told me that he once asked Rav Dessler ztz"l about answering someone who was struggling with the factual reality of a certain part of the Torah. Rav Dessler replied that it is not an ikkar of emunah that the Torah be interpreted literally, so it is better to tell the person that they don't need to accept it as literally true than for the person to altogether give up on Torah.
I wonder if those who negate other approaches even think about the consequences. I imagine that in some cases, they just assume that if they insist loudly enough that others must conform to the expected beliefs, then people will acquiesce. In other cases, they are just maniacally driven to denounce those perceived as enemies of the faith (such as myself), regardless of the consequences for those with questions that I am trying to help. And in other cases, I suspect that they might be battling their own personal demons.
Whatever their motivation, I think that they would be well advised to think about the consequences of their declaration that various beliefs are unequivocally incompatible with Judaism.