Why did people who didn't own slaves fight on the side of the Confederates during the American civil war ? What benefit did they get from slavery that they wanted to defend it ?

More can be written, but you might like to start with "Was the average Confederate soldier a strong proponent of white supremacy?", with several replies by /u/Georgy_K_Zhukov.

This is not to discourage discussion. More questions, data and debate are welcome.