I don't fault you for not knowing how the Mormons do things, but missionaries don't chose where they're sent.
They show up at the training center in Ogden, UT, and are assigned a partner and their destination.
A month later, after a crash course in the local language, they're on the ground, sometimes with a bike if they're lucky, otherwise they're given a bus pass or they walk...
They never leave their partner's side except to use the bathroom/shower, and they don't get to go home. They don't have money. They don't get to go out on a date. They don't get a week off. Two years of that, and then they come home. Someone dies or gets sick at home? Too bad. They get to make a phone call, but typically don't go home for the funeral unless they quit their mission.
Mock the Mormons all you want if you want to, but you might want to try to be a little more informed before making blanket assumptions about what is involved.