Read the rest of your link. In terms of art (which is apparently what we're going by now), white can imply all sorts of meanings:2 seconds on google,
http://emptyeasel.com/2007/06/22/the-color-white-pure-cold-and-clean/
And although its probably more of a cultural thing, white is often viewed as the color of moral purity and goodness.
- clean
- cold
- uninviting
- sterile
- uncomfortable
also, there are other meanings that they didn't discuss on that page:
- death
- surrender
- cowardice
- fairness (as in "that's mighty white of you", though that connotation has racist derivations itself)
Also, AFAIK, the thing that really made the cultural connection between whiteness and the "purity" or "virginal" nature of something was Queen Victoria's wedding, in which she began the custom of the bride wearing white... but this didn't happen until 1840, and the Book of Mormon was first published in 1830.