> The only thing not allowed (rightly so) is to produce a copy with enough similarities that it can be replacing the original.

But LLMs are replacing the original, just in different words.

And what does 'legally obtain' mean in this context? Copyrighted content is usually licensed for specific purposes. So if a license is given from training your LLM, then by all means do! But what if the license is 'for personal use'... ?