Her original remarks strike me as entirely unexceptional, and correct.
She conceded that some ethnic/racial groups suffered discrimination on racial grounds and then suggested that only her particular example was racism, the others were just examples of prejudice - perhaps you can make explicit the distinction in that which she failed to?
You can make a case, arguably, that the expressions of that prejudice are different, you can argue that one or the other is worse or more pervasive or more significant, but you can't suggest that one of them is racism and the other isn't by explaining that they're both examples of prejudice based on race.
She should have stood her ground.
She should have explained the nuances of her case better.
O.