A group that is proud of its heritage to the point where it feels it is superior to other groups, is racist.
I am a proud American. I love this country and think that it is a light unto the world. Now, as it happens many of my ancestors date back to the founding. Those who founded our great nation were predominantly of a certain ethnic background (English and Scots-Irish). It is largely from these cultures that our exceptional American culture and nation were first formed. Thus I hold in particularly high regard the culture and accomplishments of the English and Scots-Irish of the eighteenth century. I consider their culture and their accomplishments to be superior to that of others of their time.
I do not think it is necessarily racist for people to be proud of, and to uphold as superior, cultural or even physical attributes of the people with whom they share blood ties. Dutch people are sometimes proud of their size and strength. French and Italian people sometimes think that women of their ethnicities are the most beautiful. Kenyans sometimes express pride that so many of the best long-distance runners are Kenyan. Jewish people are sometimes proud of how many great intellectuals are Jewish. Etc., etc.
I don't think there is anything wrong with feeling a greater kinship toward people with whom you share ethnic ties. (Obviously these feelings are common and natural, what else is St. Patrick's Day about for example?) And I don't think there is anything wrong with recognizing the specific superior attributes of some groups just because you are a member of that group. (Otherwise I would be fine admiring Kenyan athleticism and Jewish intelligence but not English jurisprudence. What sense would that make?)
Racism is something else entirely and this is explicitly recognized by most people in most cases.
We have a black history month, we have latino pride organizations and events, Chinese New Year parades, etc. Only whites are singled out and told that if we feel special kinship toward other white people, or think that certain attributes or accomplishments of white people are exemplary, that this is wrong and racist and must be squelched.
This sort of disparate treatment is the one and only true definition of racism. Within present-day American society it is only anti-white racism that is thus widely condoned.
I was thinking of the Ubermensch and Untermensch of Nazi Germany. They turned their racial pride and sense of superiority into a license to kill those who they considered Untermensch. While acknowledging that one has racial or cultural traits that may be exceptional, it does not make your group overall superior to another. To think such is where the slippery slope to considering of them as less than human begins.
Kinship to those you have ethnic ties with is healthy. When you start thinking that others are not as good as you because they are not like you, genocide is right around the corner.
When the black civil rights movement changed from “all men are equal” to “we deserve special treatment” they initiated an American caste system which has been shown to be inherently evil. That kind of thinking, that some people need to be treated differently because of their skin color, is the root of racism, no matter what group it is aimed at.