The depends on the country, but as for the US since you mention DMCA, ML using copyrighted work is probably legal. There just is not really much case law. Talk

The depends on the country, but as for the US since you mention DMCA, ML using copyrighted work is probably legal. There just is not really much case law. Talk to a lawyer though, but depending on how risk averse you want to be there are definitely ways to avoid issues, but ensuring you can use such copyrighted works ect... Although, making a very large curated data set can be expensive.