alt Hacker NewsWhat is considered "white" now certainly wasn't in the past. It took a long time before Italians were considered to be part of the in-group. Irish and Italian people were considered an inferior race and suffered extreme racial prejudice when lots of immigrants came from those nations.
And that evolution itself tells the story of the US itself. The people in non-homogenous neighborhoods are happy and harmonious, but outsiders scared of cultural differences cause racial strife and discontent.
Those who let themselves get worked up about racism are the problem, not the non-homogenous races.
That barely scratches the surface of the bigotry that existed. Protestant or Catholic, Jewish or Gentile/Christian, Eastern European or Western European, Anglo or non-Anglo, Anglo + German or non, Southern European or Northern European - these are all lines people use to discriminate upon that I can think of just off the top of my head. That's without even getting into skin color.