The concept of an aerobatic-but-not-spinnable airplane doesn't make much sense to me, either. But there are precedents: e.g., the Globe Swift is (or at least was) cleared for light aerobatics, including flick rolls, but not spins (reportedly because the latter had a tendency to go flat after a couple of turns).
The
factory website is not very informative; it mentions "unrivalled aerobatic capability" but doesn't say what specific maneuvers are approved (or prohibited). It says that
"All Glasairs are fully aerobatic: +9/-6 G Ultimate Loads!", which is somewhat misleading (perhaps dangerously so, as it invites the unwary to push the aircraft beyond the +6/-4 G flight envelope that it is stressed for).