I don't fault the LBGT community for being angry at the outcome of Prop 8. Or even for protesting. But I think that any effort to fault any group of people for the passing of the amendment feeds into the same resentment and ignorance which they are trying to change. First off, here's an excellent blog post from an African-American asking to stop blaming his community for the bill's passage.
To say that it was "the black vote," a phrase which assumes that its some thoughtless mass which all thinks the same, which put the bill over the top,is a step backward. The same can be said of the Latino, Asian, Catholic, Jewish, Elderly, Baptist, or Evangelical "vote." No group, no matter how homogeneous, votes all the same way. And that leads me to my next group, us Mormons. Yes, members of the church spent a ton of money, were among its most visible proponents, volunteered, and a majority of LDS people voted for the ammendment. But not all of us did, and some have been vocal critics of such an ammendment. When I lived in Utah I voted against the Utah marraige ammendment. I would have most likely done the same in California (I'd have to read the thing first). People have a right to disagree and protest the Church's involvement and its stand. But not to antagonize the church in general. People need to understand that like all other groups, the mormon communuity is diverse and complex, and it always has been. For example, there are pretty well documented disagreements over progressive social policy during the Roosevelt era between President Heber J. Grant, a vocal critic, and other church leaders such as his own first counselor and staunch FDR supporter Anthony Ivins and the reliably progressive BH Roberts; of note is the fact that Utah went for FDR all four times, despite President Grant's personal, not official, criticisms.
Individuals on both sides need not demonize the other. There needs to be cool heads to talk. Agreement won't be reached by every party but we need to strive for some sort of understanding.
also check out this article from the Nation