Yeah, I know the ones online hacked the skill to begin the whole thing. What I'm wondering about is how other players who have never hacked their game are able to purchase Aptitude for their game's characters. As you said, even if you hacked other particular skills onto a character, like Kaidan's Kitsune skills, another player who discovered them online could not purchase them for theirs. They may not even show up at all, depending on how the shadow-banning works.
Why is Aptitude, a Villager-exclusive skill, able to be purchased for units who can never be villagers, while skills from beasts, Corrin's Royalty skills, etc., are forbidden?