25% Ignorance -- Don't know enough about Mormons to trust them
9% Different Beliefs -- Non biblical beliefs.
8% Polygamy -- Belief that this practice is still widespread though secret.
6% Non Christian -- Openly don't like non Christians and don't consider Mormons Christian.
5% Fear of unknown -- People don't know enough about Mormons and thus fear them.
5% Book of Mormon -- Disapprove of making your own bible
4% Joseph Smith -- Believe he is a false prophet
4% History -- racism, polygamy....
Conversely I did an article a few years back with corresponding numbers for Evangelicals relative to people under 30s (includes Christians) and you can see the stark differences:
- antihomosexual 91%
- judgmental 87%
- hypocritical 85%
- old-fashioned 78%
- too political 75%
- out of touch with reality 72%
- insensitive to others 70%
- boring 68%
As an aside the authors give an example of where Mormonism becomes non-understandable , which I found interesting. The claim to be the only restored church is viewed very negatively. Quite simply the vast majority of people are unable to even understand the claim that Mormons are making. Slightly rephrasing to this triple:
- Christ organized a church.
- Men changed it.
- It has been brought back.
- 17% -- Maybe Mormons are right
- 36% -- Mormons are probably wrong
- 29% -- Mormons are definitely wrong
- 18% -- No opinion
- Poll on American attitudes towards Mormons from 2011 (link)