I genuinely had no idea that a license wasn't required to fly a glider (or "ultralight" based on my reading). I'd imagine there is very high overlap anyway -- most glider pilots being pilots, etc.
Flying powered is a “go to the airfield and takeoff” whereas gliding is more of an all-day team sport at most clubs as there’s a lot of ground handling required for towing, winches etc.
Stuff like winch-launched paragliders excluded.
Alternatively perhaps they mean that they took some lessons in a glider as a student pilot and considered going further and getting the license.