Why do Americans claim moral superiority to Al Qaida?

For the entire first part of the 20th century "racial terrorism", previously referred to as "lynchings" and "bombings" were enacted upon racial minorities in this country. Very few of the perpetrators were brought to justice. Some of these people are still living today and have never been brought to justice. How can we claim moral superiority to Al Qaida and have a so called "war on terrorism" when we have never addressed terrorism (past and present) from within our own country among our own citizens? Sounds like hypocrisy to me...