Okay so I see two points of opposition here that I want to address.
1. The textures aren't items in game and are fairly owned by the player even if they're banned.
2. Bans can be lifted sometimes and the player can come back and use the textures.


Lets start with the first point, while it is true that textures exist as art created
outside of toribash if you go with that point it would make sense for textures
to be owned even after a perma ban since they would be the property of that
player. Thought there is a factor you're forgetting here because you're thinking
of toribash as only a game and not realizing its also a business. The texture
was sold by advertising through Toribash's official website and by doing so the
texture is linked to toribash as an aspect linked directly to it. Therefore the
texture is now on the same level as an item sold through the game. If someone
creates a texture and markets it outside of Toribash though then this would
not be the case, but once marketed through Toribash its considered part of
Toribash and should be treated as such.

Now lets talk about point 2, matters like this have a simple resolution. If an
account is permabanned and the ban appeal makes no progress over lets say
3 months then the staff can officially consider the player's assets forfeit and
proceed accordingly. Stripping textures for custom folder and redistributing
them or contacting the Artist of the textures and asking for the files if still
providable. Now I know sometimes the staff just won't be able to get the
textures, but this way at least some of them can be saved and redistributed.