No he didn't mean that, which is why he didn't say that.
First off, as if somebody has to explain to somebody who claims to be from Pennsylvania, that was no Confederate flag, that was the Tennessee Rebel Battle something something Flag that was only used for 2 months by Tennessee soldiers. Just because Republicans from the South, Pennsylvania, Boston, and a handful of Flyover States and then no one can ever remember the name of, even the people that live there, fly that flag today as it represents the Confederacy, doesn't mean it does represent the Confederacy. It don't.
Second, the Democrats did not break off the USA, the Democrats broke off themselves. They divided into two parties, one North, one South. That was short-lived as their Southern party ended when the Confederacy began. There were no Democrats in a Confederacy. But you already knew that also..