A Brief Note On Systems as Children of Other Systems
This is getting much more into Theory with a capital T than this website usually is meant to, but it's worth noting. As you probably realized, most of the forms of marginality mentioned in What Is Marginality aren't actually from a particular group violently conquering another and privileging their descendants. That mostly only applies to Racism and Capitalism, really. Gay people often are the descendants of straight people, after all.
The thing is, in very complicated ways, a lot of the forms of marginalization that affect white people are, in some ways, the children of White Supremacy. Prof. Sally Markowitz argues that the entire western system of gender, sexual orientation, and sex assignment; is actually born from white supremacy as well.  It's much beyond the scope of this website, but it's worth learning about if you have the time. I've actually written, a pared down and simplified version of Sally Markowitz's argument for another project of mine, Feminiscience. Her original article is also available here.
 Markowitz, Sally. “Pelvic Politics: Sexual Dimorphism and Racial Difference.” Signs, 2001, 389–414.