This reminds me of when I would be on doorstep and people would tell me how much they had read the book of Mormon so I would ask him what they thought about the part about Brigham Young and everybody going to Utah.
They would always tell me like “oh yeah, that was a pretty good part”
No one’s trying to make you feel bad about your own lack of knowledge. Or I guess I should say I’m not.
But your original post is asserting that this was somehow hidden and your evidence for that is the fact that you and all the Missionaries you served with (how could you possibly know this?) didn’t know either.
So us demonstrating that we all knew and we served earlier than you refutes your point