Kwanzaa is not an innocuous celebration of black history. It attempts to spiritualize that history, replacing Christ-centered theology with pagan principles. For Christians, the only principles by which to live are found in God’s word, the Bible.
Pagans have argued that Christ was not born on December 25. Insignificant. While no one knows exactly when Christ was born, the fact remains that He was born. Christmas is a time for Christians to celebrate this joyous fact.
Christ became a man to save men, not to lift up one race or culture in worship. As with any man-made religion, Kwanzaa is just another attempt to make gods of men. All Christians must be discerning when faced with these false doctrines.
The Fall of Man was the direct result of our determination to become gods. The pagan ritual of Kwanzaa is merely the old Lie wearing a new disguise.
UPDATE: Religion Link offers more links about Kwanzaa. Kwanzaa has an official site.