The Mormon’s flight to the Salt Lake valley resulted in the formation of the Mormon Battalion and an isolationist bunker mentality. That’s part of the reason but not justification for Mountain Meadows. Like the native Americans, the Mormons didn’t foresee the massive migration and colonization of the west and thought the geographic isolation was a permanent condition.
You are historically illiterate! The Mormon Battalion went from Iowa to San Diego .... was disbanded and the members returned to Utah by themselves. ...and was 10 years earlier!
A 'true' Prophet would have warned those about to embark on this great trek that many would die on the journey.
I've always found it strange that the non-fearful Mormons; who stayed behind; were NOT murdered, killed, slain, tortured or otherwise received nastygrams from the non-Mormons they lived among.
And now; today; the offspring of those folk possess the lands that the others abandoned.