The purpose of this secret poll was not just to gauge public opinion. It was fostered by that wicked one who loves to work in secret combinations. The same approach was used by the scribes and chief priests to privately plan and execute the murder of the Son of God (Jn 7:19, Mark 11:18). This is in contrast to the way in which the Lord works, For the Lord worketh not in secret combinations (Ether 8:19).
Hugh Nibley
"But if all have free agency in the Book of Mormon, all do not have civil liberties. The Zoramites, as we have seen, had a thought-police, 'therefore they found out privily the minds of all the people,' and forthwith deported 'those who were in favor of the words . . . spoken by Alma'" (Since Cumorah, p. 350)