A "hive" mentality, or "collective" mentality was the first thing I thought of when I was deep inside the Mormon Church, but a "protective" mentality probably would be a much more accurate description. They are a very closed group, protective of their members and mutually supportive when they need to be. The main feeling was one of never having to face adversity... or shame....alone. You are welcomed into the group, you must face the group if things go wrong, and the group decides your fate. Once repentance is achieved, the group magnanamously welcomes you back.
Derek was an outsider, not only of the Mormon Church, but of his family itself. He chose, however, to not indulge in any other typical vices that the rest of us deal with....alcohol, caffeine, smoking... because he just was not interested in any of it, though curious enough to try all of it to at least experience it once. His friendship with me, a non-Mormon, was probably another example of that. His best friend up to then was a Jack-Mormon, who fell off the church bandwagon in all ways. I met Derek through this mutual acquaintance, who was dating a close friend of mine from high school, (who, as it turned out, is now my wife). Derek and I had so many things in common, plus our personalities meshed so well, that we became friends almost immediately.
But the one thing that kind of stuck between our friendship was the Mormon Church. His loyalty to it was amazing, considering he did not fully accept all the constraints of it. His family was always so nice to me, I felt extremely comfortable at his home. Only later did I learn how fake all of that was.
Within the last ten years, Derek's mother died of cancer. Almost immediately, his father started to date another women of the church and married her within six months. Before then, Derek, who always was a very hard worker and always thinking of ways to make money, went into business with his father involving an idea that Derek came up with and, with Derek doing the hard work and sales, just needed his father's financial help to make a go of it. His father agreed on the stipulation that Derek bring in his younger brother into the business as well. The brother, Clay, never had much drive or direction and his father wanted him to have a career of some sort, so Derek agreed.
Once the company Derek developed and worked so hard to make a go of took off, his father sued Derek to take full control of the company and won the lawsuit, at which time he gave full control of the company to Clay and kicked Derek out completely. Derek was so devastated he could hardly function. My wife and I only communicated, via emails, with Derek's wife during this time, who told us the story. We last saw Derek at his daugher's wedding down in Vallejo, about four years ago. His whole family was there, except his sister, and while they were as friendly as ever towards me, Derek would not talk to them, or sit with them, and never acknowledged them the whole day. He has since moved to Idaho and we don't see them anymore, though the wifes email each other occasionally.
All that open, friendly, welcoming attitude, and you never really know what lurks underneath. Needless to say, I don't necessarily blame the Mormon Church for Derek's family turning out to be rather evil, but I also can see how the mentality of the closed society of the church could cammoflage the reality so well.