No, he (insert gadol here) isnt perfect. Yes, hashem hides things even from a navi (yackov avinu didnt know yosef was alive) for whatever reason.
However, all doubts go away when you understand the concept of “daas torah”. As long as someone feels they are just as smart, or almost as smart, or have access to the same data/info and can make decisions too, then yes, they start questioning every time a Rav says something. When you recognize that there are those smarter than you, you listen to what they have to say. I believe it is the sfas emes (dont shoot me if I’, wrong) who explains that why was moshe “anav mikul adam” because he had the greatest recognition of HKB’H and had the greatest understanding that everything is because of him, the more one realizes that, the more humble they are. I think much of the questioning stems from peoples arrogance. If I offended anyone I apologize, despite the fact that it is your arrogance that takes affront to what I wrote.