wotc decided to make him a human warrior, for whatever that is worth.
I am aware of what you said, my point is that it's not really meaningful when conceptualizing interactive gameplay. Emotionally it might feel annoying to look at this immortal piece of cardboard, which is an important part of game design, but from a mechanical standpoint it really doesn't deserve to be called uninteractive. It essentially just turns your cards into a complicated modal spell, but you wouldn't make any similar complaints that charms are uninteractive because there's no way to interact with your opponent choosing mode to play.
Secondly, I really don't think it matters. Let's say they printed a card with "Target opponent leaves the dungeon" or "Target opponent ventures into jail (it's a dungeon with three empty linear rooms)", would that make it more appealing to include in a cube? You probably wouldn't add the aforementioned cards because of how narrow they are, even though you could now technically interact with dungeons. If you support
Ajani's Pridemates in cube, do you also add cards that explicitly prevent life-gain? If you cube cards with rebound, do you need
Rift Sweeper to deal with the card in exile? Is graveyard hate an essential inclusion in cubes with flashback cards?
In practice, most mechanics in magic can be interacted with meaningfully through the normal attack vectors, and dungeons aren't an exception. And I would guess that most cubes have a lot of gameplay elements you can't interact with in the context of that cube, that nobody is particularly bothered by. As an example, I play a lot of Suspend cards, and there's no way to manipulate those cards while they are suspended, but it's fundamentally just a different way to play the spell, it's not an aspect of the game you need agency over. Likewise, you seem to play a single copy of
Carrion Beetle as the only way to interact with the numerous recursion effects in your cube like
Yawgmoth's Will,
Replenish and
Karmic Guide, and you play cards like
Mother of Runes and
Argothian Enchantress that is way more likely to make me go "how the fuck do I deal with this" than any deck venturing into a given dungeon that's not called The Undercity.