Anthropologists categorize cultures as either guilt based or shame based. (See here for a quick summary of the differences between the two.) The U.S. and Europe are thought to be guilt based due to the influence of Christianity. Cultures like that of Japan, Mexico and ancient Greece are thought to be shame based. The difference is the relative power of social conformity and the role of internal versus external morality. The Southern U.S. is more shame-based, compared with the more guilt-based North and West. Honor plays a larger role in shame-based cultures. Conscience is more important in guilt-based cultures. (There’s a reason that duels were popular in the South but not in Minnesota.)
I think LDS culture is moving more towards being a shame-based culture. It is not alone in this; to me this is the biggest difference between U.S. Evangelicals and mainline Protestants. The evangelicals are more shame based, while the protestants are guilt based. Mormons are following the lead (and political causes) of their Evangelical brethren.
“Avoiding the very appearance of evil” is classic shame-based behavior. The pressure in LDS culture to use particular and instantly recognizable vocabulary and set phrases is a sign of a shame-based culture. Rigid gender roles are another characteristic of shame-based societies. The rhetoric about "defending the family" is part of a shame-based culture where honor is to be defended.
Unfortunately, I think the larger picture can be summarized as the Church following the political lead of U.S. Evangelicals whose worldview carries over elements from the shame-based culture of the American South. This is absolutely not native to Mormonism. It’s a relatively recent import. If the Church leaders weren’t so obsessed with getting the popular kids (the evangelicals) to like them, we could have avoided this mess.
(See here for a related post on one of the Mormon blogs.)