Ive been thinking about this a lot and if you think about this like they are selling a stolen product then it can be framed differently.
Say I take several MegaMan games, take a copy of all the assets, recombine them into a new MegaMan game called "Unreal Tales of MegaMan". The game has whole new levels inspired by capcom's Megaman. Many would argue that the work is transformative.
Am I allowed to sell that MegaMan game? I'm not a legal expert but I think the answer to that would generally be no. My intention here is to mimic a property and profit off of a brand I do not own the rights too.
Generative AI uses samples of original content to create the derivative work to synthesize voices of actors. The creator of this special intention is to make content from a brand that they can solely profit from.
If you used an AI to generate a voice like George Carlin to voice the Reptilian Pope in your videogame, I think you would have a different problem here. I think it's because they synthesized the voice and then called it George Carlin and sold it as a "New Comedy Special" it begins to fall into the category of Bootleg.