Social class and social justice

An acquaintance recently observed that there's a certain kind of White guy Social Justice Warrior who sometimes starts ranting about how It's All Really About Social Class. They liked it when I made this observation:

The invisibility of class in totalizing identity politics is a big problem. But the classic Marxist dismissal of all social justice questions as just devolving to class is even more corrosive. And if you're coming from a totalizing identity politics framework where the only ground of authenticity is to claim that you speak from the experience of oppression, it's appealing to claim that the oppression you experience is the only one that counts.