Indeed one should learn something every day. Lateral Stability (static or dynamic) is not normally defined with regards to rolling motion. The 'roll' is directly linked to a slip and if you bothered to read all of the document you quoted, you would note that stability in a slip (roll) can be achieved with a wide variety of methods. Also, from FAR 23:
Sec. 23.171 General.
The airplane must be longitudinally, directionally, and laterally stable
under Secs. 23.173 through 23.181. In addition, the airplane must show
suitable stability and control "feel" (static stability) in any condition
normally encountered in service, if flight tests show it is necessary for
safe operation.
However, the requirements of 23.177(b), static lateral stability,
do not apply to to acrobatic category airplanes certificated for inverted flight. So, in this circumstance, there appears to be no legal requirement for a Super Decathalon to be statically stable. Whther it is or not, I do not know.