I think an overlooked aspect of white supremacy in speculative fiction (and thus in speculative fiction TTRPGs ) is the idea that humans are inherently colonialist. That slavery and cultural genocide are born out of natural, internal, immutable human drives.
Like, no. Colonialism was a uniquely white Euro-American phenomenon. War? Of course, that’s universal. Patriarchy? Basically everywhere. But the specific drive towards the enslavement, disenfranchisement, exploitation, and dehumanization of people you see as other? That’s not a human thing, that’s a product of Euro-American culture having deep-rooted problems and sicknesses that it has yet to fully excise.
tldr read Discourse on Colonialism