First we should note Confederates claimed Kentucky & Missouri and sent armies of conquest to hold them.
They also invaded Maryland, hoping to flip it from Union to Confederate.
Second, those were all Southern slave states except Nebraska, which was a territory, not a state.
Northern free-States had all gradually abolished slavery by 1860 and only a handful remained in one Northern state, New Jersey.
In the mean time Northern freed-blacks increased to over 200,000 by 1860.
As Daniel Patrick Moynihan famously said:
“Everyone is entitled to his own opinion, but not to his own facts.”
In this case you have your facts wrong.
There is no disagreement among scholars or documented history on the fact that there were only 11 states in the Confederacy and Kentucky, Missouri and Maryland are not among them.
The eleven Confederate states were South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, Texas, Virginia, Arkansas, Tennessee, and North Carolina.
Delaware, Maryland, Kentucky, and Missouri were known as Border States.
Once West Virginia separated from Virginia it too was considered to be a Border State.
Border States remained loyal to the Union but state citizens generally had divided loyalties.