All I know is that LDS teenagers have statistically higher rate of suicide as compared to non-LDS ones. Another thing is interesting, however: non-LDS peers living in LDS communities have comparable to LDS (e,g. higher than in the country) rate of suicide, too.
The reason for it is not known. We can talk about “nurture” (e.g., parents of non-LDS kids ready to settle in, say, Utah might already share certain views that would make them more similar to LDS, hence, the same stressors on their kids) vs “nature”.
“Nature” would be totally opposite. Non-LDS teenagers living, say, in Utah might be the kids of “lapsed Mormons” sharing the same genetic makeup with LDS kids. And, as we know, there is a certain genetic/ethnic predisposition to suicide (easy to Google what two countries are nr. 1 and 2 in the EU, for example).
Homicide is more complicated because religious/spiritual beliefs might easier hold people from homicide than suicide, so I would not be that blunt.
All I want to say is- among other things, Amish communities may be lacking some genetic diversity. LDS communities are getting influx of new genes but before, were also self-contained. So we can not take two groups with unique history and compare them to the rest of the world. Too many confounding factors.
Just one of the articles I saw.
ETA: family annihilation is still a very rare thing. In cases like this, everything might be discussed because prevention is penultimate. So I think that asking "what could have prevented the Humistons from losing their lives to an extreme case of domestic violence?" is a valid question. What protective factors could have been utilized and were not? We don't know and it is bad. (How many things could have been prevented if the story of the Columbine was known sooner?)
I think, omerta never helps. It is good that we share different views here.
Yet: comparison with a group that is battling its own, yet unexplained, problem is not going to help at all.