The porn bit gets headlines, but it isn't the core of the issue.
All of these models retain a representation of the original training data in their parameters, which makes training a violation of copyright unless it was explicitly authorized. The law just hasn't caught up yet, since it is easy to obfuscate this fact with model mumbo-jumbo in between feeding in voices and generating arbitrary output.
The big AI players are betting that they will be able to entrench themselves with a massive data advantage before regulation locks down training and effectively kills any future competition. They will already have their models, and the worst case at that point is paying some royalties to people whose data was used in training.