>>48058405A lot of folks say that Absol's Type is dumb because it's Dark only because humans think it's evil, but that's not why it's Dark, that's them misunderstanding. Usually Dark Type pretty explicitly means " this creature uses mean underhanded tactics in battle" but that isn't always what it denotes.
It is possible to be Dark pokemon with dark powers and choose to not use them for ill. Sorta like how a Grass Type can literally be a plant, or it can be a regular animal with geomancy. Dark Types like Murkrow have a theme of bad luck, and Yveltal has doom. Absol has both, it's just not using them in a typical way.
Also it has a yin yang for a face. The fact Absol SEEMS evil but actually isn't is very much the point. But that doesn't mean it doesn't fit as Dark, it means it uses its dark capabilities for noble causes.