tsogud on 07 March 2016
The only reason I could think of is because in Japanese Dark type is actually named Evil which represents dirty underhanded tricks, being mean/nasty, and sly/stealthy as well as just darkness. So in that sense I guess having a gym leader who is supposed to be a role model teaching children to use dirty tricks to win and to be nasty wouldn't be too great.
I would love a Dark type gym though it's one of my favorite types along with Fairy and Ghost.
