Why is the confederate flag considered raciest?

The confederate flag is considered to be racist by some people because it represented the south in the civil war, and one of the most memorable issues of that war was that of slavery. The south used black slaves and were defending slavery because their economy was almost solely based on agriculture and they believed they needed slaves to work on the plantations. As a result, the confederate flag is now associated with the support of slavery and the subjugation of African Americans.