[A] Greninja Can't Learn Dark Pulse?

[Tacos 205]

So after beating Luna and getting the ever so glorious TM of Dark Pulse, (*heavenly sounds blare and glorious light descends from the sky*) I found out that for some reason Greninja is incapable of being taught it through TM. Is this a bug or was it purposeful by Ame to force us to use Night Slash? ;-;

Source: http://www.serebii.net/pokedex-xy/658.shtml, and also that my Greninja was able to get it in my Pokemon X

[Arkhi 199]

Most Gen 6 Pokemon haven't had their TM/HM movesets updated. If you ever want to see if it's in the process of being fixed, you could read the Development thread. A majority of the non-coding/map design/plot work that can be accomplished by the community is often posted there.