… aren’t receiving revelation themselves. Otherwise, they would know “how it works.”
“Revelation” covers many things/categories, and includes many degrees, from the faintest whispers and intimations of the Holy Spirit, to discernment, to “confirmations” (the ternary yes/no/no-answer), to dialogic prayer, to powerful soul-touching indwellings, to bursts of intelligence, to open visions that span time and space and cross the veil. Examples of those categories are in scripture, both ancient and modern. Full-time LDS missionaries teach some of those basics in their standard lessons for investigators.
If one has received a spiritual testimony (revelation) that the LDS church is what it claims to be (ie, the “foundational claims” are true, and that true priesthood/godly authority continued through Brigham Young and his successors), and has also received revelation (in any of the forms/degrees mentioned above) in and for their callings and spheres of influence, then they would know “how it works.”
They would know how God is a God of order, and is no respecter of persons. They would know not just the “rules” of God’s interaction with mankind, but the heirarchy of rules, such that an apparent exception is not really an exception, but is in accordance with a higher rule/law. They would know that if God inspires and pours out His Spirit upon the rank-and-file in their callings, how much more would He do so for the leaders who carry a greater weight and scope of responsibility.
I used to think the doubt-mongers just didn’t understand the scriptures, or the “rules” of how God interacts with us. But now I’ve come to believe that they don’t have a (or lost their) testimony of the restoration, and never have received (or ceased receiving) personal revelation.
Note that I’m commenting upon the disseminators of doubt, not upon all doubters, nor upon questioners, because no one I know has perfect faith. (Sometimes disseminators of doubt slyly pose as questioners.)
Sometimes you can detect a disseminator of doubt posing as a questioner by directly asking if they believe the foundational truth claims of the church.