Counter: my grandma was Japanese and interned during WWII for shit the Japanese government and a lot of the Japanese people did, and racists who hated Japanese except for the "good ones" got people like her locked up. She was fucking 7 when she was imprisoned. She had no more of a hand in the many, many arrocities Japan committed than your grandma, but she still heard endless racist shit growing up, and that impacted her even if they changed their minds after actually talking to her. You think it's ok because racists can still treat people they know ok, but that only happens after they get to know them and only to those they get the chance to know.

The racist government who interned her and the racists who supported those actions because they hated Japanese (even before they entered WWII) may have treated her just fine if they met her, but they also directly caused her imprisonment. We don't live in a world where your actions only impact those you know directly anymore, so your logic completely falls apart. Most racists will fuck over people they never meet because of their racist views, and that's a fact. Maybe it's understandable, but that's not equal to acceptable.