Shinbai Academy is a high status school created for the purpose of teaching students the importance of competition in life.
It is for that reason that the different uniforms for each season, while provided for each and every student free of charge, vary greatly in quality of fabric and proper size measurements based off of a students grades, achievements and overall status.
The winter uniform our school appointed model (and kidnap victim) is sporting now is of the highest grade and works to keep out the cold without making the body sweat. Nearly perfect insulation and incredibly breathable fabric make the Shinbai Academy's uniforms an incredible feat of both fashion and science.
Luckily, Kitsune gets to keep this outfit due to him being a good sport about this forcefully imposed photo shoot and the many kidnappings over the years (you didn't think he just wears all that stuff for the fun of it did you?)
Plus he's like a triple A student!