Earlier quoted context omitted.
Most stars are red dwarfs. Of the 131 stars and sub-stellar objects within 20 light years of the Earth, 101 are red or brown dwarfs. JWST/NIRISS has limited resolution, it's not going to be shooting spectra of exoplanet atmospheres of systems 50,000 light years away. They're just measuring every exoplanet system.
Fun facts about red dwarfs* If you look up on a dark night, you can see 5 to 10 thousand stars. For every star you see there are 8 red dwarves. Not one of them is visible to the naked eye. No red dwarf has died of old age yet. They live trillions of years and the universe isn't old enough. Proxima Centauri might not be part of the centauri system. It's orbit is so long (80,000 years) that we can't tell if it is orbit…
Heck, TRAPPIST-1 itself isn't eye-visible. It's only slightly bigger than Jupiter! But these systems are hugely overrepresented in exoplanet surveys-- since we've only been hunting for exoplanets for a decade or so via the transit method, most of them have been found orbiting red dwarfs: the host star is so dim that transits take a big chunk out of their light curve, and the planets huddled up close to the star orbit so quickly that you can get the required three transits in a mere ten years of observation time.
It's a safe bet that there are gas giants like Neptune out there, but by the transit method it would take four centuries to find them! We invented the "hot Jupiter" category after Kepler launched, without nothing that we won't ever find "normal" gas giants without interstellar probes or space telescopes 10 km across.
