The cutting area includes the overhang area at the front of the machine. The 33" x 33" is a total travel specification which doesn’t take workholding and endmill diameter into account. The 32" x 32" in Carbide Create is a compromise figure which leaves room for both and margin to spare — the stock size is a previewing limit only — you can make arbitrarily large geometry and toolpaths and they will be exported to G-Code.
Some folks have made spoilboards which extend past the front of the machine so as to have the entire working area supported. A few folks have reversed the gantry so as to increase the area which is on the wasteboard — there’s a post on that here: Alternative S3 construction to move usable space