I wish we could be talking about the power imbalances of corporate bodies exercised through the use of capital ownership, instead of squabbling about how that differential is manifested through a specific act of piracy.

The reason we view acts of piracy different when they are committed by corporate bodies is because of the power of their capital, not because the act itself is any different. The issue with Meta and OpenAI using pirated data in the production of LMM's is that they maintain ownership of the final product to be profited from, not that the LMM comes to exist in the first place (even if it is through questionable means). Had they come to create these models from data that they already owned (I need not remind you that they have already claimed their right to a truly sickening amount of it, without having paid a cent), their profiting from it wouldn't be any less problematic - LLM's will still undermine the security of the working class and consolidate wealth into fewer and fewer hands. If we were to apply copyright here as it's being advocated, nothing fundamental will change in that dynamic; in fact, it will only reinforce the basis of that power imbalance (ownership over capital being the primary vehicle) and delay the inevitable (continued consolidation).

If you're really concerned with these corporations growing larger and their influence spreading further, then you should be directing your efforts at disrupting that vehicle of influence, not legitimizing it. I understand there's an enraging double-standard at play here, but the solution isn't to double down on private ownership, it should be to undermine and seize it for common ownership so that everyone benefits from the advancement.