I believe these men, of which 2 former US generals before te civil war, mainly defended their homelands. I have read my fair share of US civil war books back in thed ay and very few people even cared about the whole slave issue. Many in the South even agreed about ending slavery and often didn't have any themselves (or set them free before the war). Also, slavery was often used as an easy way to "sell" the War in the Union states because men needed a cause to fight and die for.
Btw, dont forget that General Lee was offered command of the Union forces before deciding to defend his home state instead.
And I was honestly surprised that all of the sudden these statues were a big deal even though they have been there for decades, often even pre-WW2.
I als don't believe any side really cares about the slavery backstory here. People are just unhappy and are looking to find/make a cause and start trouble.
People are easily triggered these days and you can apparently make them angry about almost anything, even a statue.