I think the assertion was that “white working class male[s] … are racists.”
It’s an oft-told tale. Whenever it comes up, I’m reminded of a particular quarrel about how history should be written.
Remember Orval Faubus and the Little Rock Nine? It’s a complicated story but, for decades, historians, few of them “working-class,” wrote it in such a way that, apart from African-Americans, the heroes were wealthy liberals. When someone finally examined this detail, it became clear that crucial support for school integration in Little Rock came from … the "white working class."
Here’s some context (Mike Pierce, Arkansas Historical Quarterly, 70:4 (2011)):
With that as background, consider what journalist Dan Wakefield wrote specifically about the campaign to defeat Faubus and the school-segregationists (The Nation, October 11, 1958):
As Mike Pierce puts it:
“[The pro-school-integration] campaign witnessed more interracial cooperation than many historians have realized. This is because they were looking for cooperation between blacks and white elites rather than between blacks and working-class whites.”
A final paragraph from Mike:
Sixty years ago, unions were a binding force on the left. How unions affect “race relations” today is, I suppose, part of your argument.