I'll go a bit beyond my post. The relation of class to capitalism defines the system. And a significant part of Marx's income was from Engels. On the substantive issue. I don't think class is more fundamental than gender or race.
Gender is a historically determined reproductive division of labor.
Women's liberation must be equal with workers' liberation in the Marxist project. The capitalist mode of production is as fundamentally defined by the division of labor based on race and colonialism as it is by wage-labor. Racism is an infrastructural element , not superstructural in origin. That sounds like an anti-independent women's organisations line to me.