I think it's the same thing as the "don't mod the game" for FFXIV. Legally covering their asses. But like- They won't do anything if the fans don't make it a problem (i.e. tagging the jockeys, trainers, etc. in "inappropriate" art).

Not only did they remove that notice btw, but they released an Uma that literally goes Yandere and loses her grip on reality to the point it fully affects the player and they give in to their "instincts".

Related video youtu.be/2fdxAZoHgl8?...

Oh, I'm aware. I love her.