It all depends on the meaning of "is" is. And maybe "not" too.
I'm reading this thread backwards so I'm aware of Carrol's irritation and your reference to the contingent and historical accounts of the origins of North American slavery. But perhaps you're conflating the pursuit of a political agenda - mobilizing a cross-racial anti-capitalist solidarity - with explanations of economic and social inequalities and the struggles involved. And that's notwithstanding the invocation of praxis.
Empirically supported generalizations such as "whites or white workers have materially benefitted by racism or racialized work, educational, housing opportunities, etc." probably require a lot more historical nuance and detail, especially of the precise benefits gained. Perhaps whites don't gain exactly in the same manner as capital gains from labor, but enslavement, restriction, exclusion, segregation, terror, cultural hegemony, etc. have generated an array of material and symbolic benefits, advantages, privileges for some, many, and all whites. We can think of the kind of claims Kovel makes - boosted self-esteem, scapegoating, enhanced status - suggesting psychological benefits. There's McIntosh's list of advantages and privileges of whiteness, most importantly the presumption among whites that they represent the moral benchmark from which all others are measured. There's the literature around Bonacich's claims that the practices of white racism *can* reduce competition and faciliate exploitation benefitting white workers. At least we need to acknowledge that inequality has a rational basis: I won't take from you unless I have the means to do so and you have something I want.
This doesn't mean that there isn't a material basis around which to build solidarity. It does mean that the material basis for that solidarity requires a clearer articulation, no? If whites or men represent the dominant groups in racial and gender struggles, and that seems a fairly safe assertion, then they do indeed share some similarity to capital. Their gains come at the expense of others and so the benefits they enjoy come largely from the exercise of power. Sheer power, not superiority or merit or whathaveyou that have been deployed to rationalize the exploitation and inequalities. And so it *can* be in the interest of some, many, most whites or men to protect their advantages. It seems that to ignore this is to invite peril. Or futility.
Dennis Breslin