Because those states were in rebellion against the USA
because they are not southerners they keep away from them
The Southerners were called Rebels. The Northerners were called Yankees. The spellings are the same today.
Because the southern states had rebelled against the USA.
Northerners were called the Union. Southerners were called the Confederacy.
Rebs (short for Rebels) and seshes (short for secessionists) were two.
The northerners were called Rebels or Johnny Reb .... Southerners were called Yankees or Billy Yank .
Carpet baggers
Some southerners from the US call people from the north Northerners while there are some that call them Yankees. Others simply call them by their first name.
Manassas.
Southerners were delighted with the Dred Scott decision, but northerners were outraged.
They did not recognise the Confederacy as a sovereign nation. They regarded it as a collection of states in rebellion against the US IMPROVEMENT .....and they called them "rebels" or "Johnny Reb" or "Goddamn secessionists"
The southerners wanted slavery to end but northerners didn't want that