Firstly, no kidding, of course it's "illegal" and "Piracy". Secondly, there's an argument that the infringement happens only when the LLM produces output based

Firstly, no kidding, of course it's "illegal" and "Piracy". Secondly, there's an argument that the infringement happens only when the LLM produces output based in part of whole on the source material. In other words, training a model is not infringing in itself. You could "research" with it. But selling the output as "from your model" is highly suspect. Your business is then based on selling something based other people's work, that you do not have rights to.