Terrorists? No.
The Confederate armed forces, despite individual depredations, didn’t target innocent civilians and didn’t necessarily believe that God (or the Bible) told ‘em to participate in secession.
On the flip side, an argument could be made that segments of the Union army did participate in what could be considered terror-related activities - such as the March thru Georgia.
Manse Jolly
This Pennsylvania Yankee would tend to agree with that statement, but there was some rough-fighting on between Kansas and Missouri both before, during & after the official dates of the Civil War. Looked pretty much like organized terrorist attacks by today's standards.