None of the jobs employed by the WoL are neutral or evil. They are ALL good since the WoL can only be good.

The cases of dark magics or dangerous techniques used by the likes of Dark Knights, Black Mages or Warriors are not exceptions. The job quest lines for these jobs are very explicit that you are tapping into dark and dangerous abilities and learning to control them for a good cause.

Black Magic is illegal not because it is evil but because people cannot be trusted to learn to wield it safely. It also once caused an Umbral Calamity, though ironically this was alongside White Magic, so if that makes Black Magic evil it also makes White Magic evil (this is actually why the Padjali are incredibly reluctant to teach anyone their art).