Red's naming screen/trainer card sprite in the original Pokémon Red/Green/Blue versions permanently corrupted my fashion sense as a kid so I still think poofy letterman jackets are the coolest type of jacket possible to be honest

I think this is generally how Jazz likes to dress! It's sort of an interesting combination of "masculine" and "feminine" fashion choices... I think he likes clothes like this that show off his chest, since he's proud of his top surgery scars, but he also tends to wear things like skirts or very baggy shorts as like... the clothes for his... pants equipment slot... probably due to his big ol' talon-feet accidentally ripping up one too many pairs of more form-fitting pants while he tried to fit them through the pant legs, so he just decided he'd had enough of that, haha