Yeah. I'm from a working class background -- a white working class background. Not news to me.
What I'm talking about is probably peculiar to the u.s. because of slavery and jim crow. I think there's a long history that shapes the tendency for the black middle class to be more socially conservative as a strategy for assimilation. (Other oppressed groups have done the same, so I don't mean to single out blacks per se.)
An excellent overview on the issue from a black nationalist lesbian is E. Francis Wright"s _Dark Continent of Our Bodies: Black Feminism and the politics of Respectability_. Wright takes black nationalists to task for sexism and black feminists to task for hetero/sexism and the silencing of the voices of black gays and lesbians in an attempt to demonstrate their acceptability to the dominant society.
Another thought-provoking overview is Michael Eric Dyson's tracing of a black middle class war on poor and working class blacks in _Is Bill Cosby Right? Or has the black middle class lost its mind?_
Dyson teases out the history of the women's social uplift movement (sometimes called the "club movement" http://www.lib.niu.edu/2003/iht1020311.html -- which does have a counterpart among white middle class women who tended to target _prostitutes_, which Laura Agustín has described as the "helping (save prostitutes) professions" -- which white middle class women engaged as professional employed women in social service agencies, private and public:
The social uplift women's club movement targeted black women who engaged in behavior that shamed their community. This wasn't a factor among the white working class though it, too, was targeted by social uplift movements too. However, you _do_ find it among Jewish middle class women who worked in tenement projects to teach working class recent Jewish immigrants proper middle class habits (cooking, dress, social interaction, manners) because they were seen as embarrassing more established middle class Jews who were also trying to gain a foothold as acceptable to whites -- as also one of them.
At any rate, middle class black women swooped into working class black communities in the post-civil war era. With freedom, Dyson explained, blacks took to dressing in the finery they'd never been allowed to wear. Women took to wearing clothes deemed too provocative. Men wore flashy suits. Both women and men cultivated rituals of social exchange: mastering habits of presentation, style, stride, etc. to express their newfound sense of freedom. (You can also read about this, tangentially, in Katrina Hazzard-Gorden's excellent, _Jookin_, which documents the rise of social dance forms and juke joints in the South during reconstruction.)
Whites quickly and harshly reacted to such brasen and "uppity" displays. In response, middle class black women established a social uplift movement to teach working class black men and women how to dress, behave, walk, talk, etc. so they wouldn't "shame the race."
The goal was, of course, to impress upon whites that they were acceptable, that they adhered to white middle class norms of sexuality, comportment, etc.
So, my point is that there is another dynamic to consider here -- especially when you look at the data for blacks and see how the issue of class doesn't make a dent and, in fact, you can see social conservativism _rise_ with social class status -- at least on the issue of gay marriage.
You can read more about what Elizabeth Higginbothamcalls "the politics of respectability" in her article "Imagining Lynching: African American communities, Collective Memory, and the Politics of Respectability," in _Reflections on Anita Hill: Race, Class, and Power in the United States.
On a related note, let me also recommend Lawrence Graham's _Our Kind of People: Inside the Black Upper Class_ by Lawrence Otis Graham. I wrote about it here, so an archive search will turn up whatever ramblings I posted. Graham is a member, so not critical, and he's interested in chronicling the history of the black elite, particularly as they emerge in urban centers. He displays and examines a tendency toward a desire for assimilation but a cultivation of separate black elite groups (sororities, fraternities, elite clubs for children such as Jack and Jill), which are cultivated to create a politics of what I'll call assimilationist black nationalism which I wrote about in my previous posts.
What was interesting to learn was that they openly embrace the identity bourgeois. Two examples of this can be seen at these blogs:
Jack and Jill politics, A black bourgeoisie perspective on U.S. politics http://www.jackandjillpolitics.com/
Boughetto News, , unfortunately doesn't exist, but this was its tagline:
This is real thought-provoking commentary on pop culture. And you? You're probably bourgeois - and as such it is your job, your mission to help the ghetto among us. I will do my part in showing you what you're up against. That's right. "Helping us see the madness ... to stop it."
They are operating from the premise of the old web site, "Ghetto or Not?"
Or the currently popular one, Hot Ghetto Mess with the tagline, "We got to do better." http://www.hotghettomess.com/faq/ The author's quote on that page is from Malcom X: "My hobby is stirring up Negroes." (Which is a whole related topic: the influence of Black Nationalist separatist movements.)