My great-grandfather left his home in Mexico, New York to fight against slavery. The Confederate flag represented slavery and nothing else. He died in the 19th century but states in the South still have the Confederate flag flying over their statehouses.
The Confederate flag stands for the rights of white people to own African-American people. The Confederate flag stands for racism. The Confederate flag represents a time in which Americans believed Thomas Jefferson was wrong when he wrote that Americans were entitled to life liberty and the pursuit of happiness. (Jefferson of course did not free his slaves and was a living denial of the Declaration of Independence.)
Today when states have to debate whether to keep the Confederate flag, America looks like a banana republic. When Republicans mostly stay silent on this issue we can see how racism is a threat to this country.
The fact that this deserves a debate makes America look foolish to the rest of the world. Take down that flag.