It means that they are the soldiers in mindset these days (looking back now), that rode into places like Gettysburg etc to fight the Demon-crats who wanted slavery to continue.
They reside everywhere now, because after the war the government occupied the south by keeping U.S. military installations all over the south in which was conquered by the U.S. military in blue back then, and this over the grey.
The blacks thinking that the south is still the seggragated prejudice south is just hilarious. The mixture of Americans United are everywhere today. Sure there will always be racist everywhere in America, but they aren't defined specifically by party, area, community or group these days.
You can only identify them by their characters, and by their speak and/or actions they take. They are not identified by state or community these days also. Thought you knew this by now.
Trying to keep the south as this racist area of the country still or trying to label republicans as these old time racist Demon-crats uh is just hilarious and laughable really.
So here we have people like the OP attempting to make us all dumb here, but it ain't happening... LOL
Quit making the south your Boogeyman or the republicans the same, and just join the union with all Americans no matter where they live in the country now, and start rebuking racism no matter where it exist in the country.