It seems a lot of people don't have any problem with God being violent, but if you consider how many evil
folk are running
around on this
planet, even just at the moment, it seems God prefers peacefulness to blasting them away.
So why would He want to tell those
folks about ALIENS from another
planet, let alone that the Earth revolved
around the Sun and not the other way
around... And, according to the gold plates found by Joseph Smith, He DID visit other areas including the Americas where he appeared and taught natives there as well.