Sure, slavery didnt literally benefit every white person. But youd be hard pressed to find a white person today who never experienced any form of white privellage
https://en.wikipedia.org/wiki/Philadelphia_nativist_riots
https://en.wikipedia.org/wiki/Anti-Irish_sentiment
https://www.history.com/news/when-america-despised-the-irish...
I find nothing ahistorical about what I said.
If you go further back and see what Cromwell and others did to the Irish (the first British colonization was in Ireland), and then extend that to the US, where that kind of hatred was shared by Nativists, it is certainly not inaccurate, even if the discrimination is of a different from than what Africans faced.
I dislike the notion that because people aren't African they weren't victims, too, which gets bandied around a lot. We all have tragedies and I see no reason to ignore the plight of one to make the point about another (which the parent post does, wrongly).
Irish Catholics and many other groups had no special place as immigrants, they didn't get positive points for not being African. That's the unfortunate truth with all forms of discrimination, it's hardly something limited by class, race or time.