Sam2 I can believe that sincere people trying as you say to be Ovdey
H-sh-m, can have questions about MBP and about Kaporos.
But usually (I’m not saying necessarily everyone, but probably most)
of those who have their minds totally made up that such practices are wrong and should be forbidden, also have other serious problems in other areas of Yiddishkeit that show (Or would if their neighbors and others in the community knew about all their private thoughts about such things) they really are not so frum or really have all the sincere emmunah and bitachon they seem to the outside world like to have in such abundance.
I knew for example someone who was the epitome of this
type of person.
She was well liked by her bais yaakov students and a perfect mother and friend and hostess etc…
But she hated kaporos and later told me she thought that the rabbis
had just made up the halachas to benefit men and that women had been
cheated by the male dominated system.
And yet anyone who knew her would have been totally certain she
was the ultimate frum wife, mother, teacher and friend.
Only G-d can look into someones heart and know for sure if they
are as sincere an Ovdey H-sh-m as they appear to be.
Many have talked to me about the issues about these practices and in many cases I have also learned some intimate details about their private
lives and about their sincerity, and every one of them who
thought kaporos and/or MBP were totally wrong, also had serious issues with belief in Torah in other areas, as well.
But their friends and neighbors and even their own families (some have confided in me and I have kept their confidences) in some cases, simply did not know, and thought they had as much emmunah and bitachon as anyone could hope to have.