Are eastern Europeans white? I feel like many American white people might say not really lol but history is interesting overall. We don't have to compare traumatic histories to appreciate their similarities and differences. We can acknowledge global white supremacy and the after effects of America brand of slavery in the current day along with noting other periods of slavery history has witnessed. The only issue is when people try to dismiss the clear after effects of chattel slavery using whataboutism and bad faith arguments.
It's historical record that white people were slaves. as long as proper context is given based on the discussion at hand and comparison isn't used as a means of dismissal, we should be able to acknowledge both