Using copyrighted material for research is fair use. Any model produced by such research is not itself a derivative work of the training material. If people use it to create infringing (on the training or other material) they can be prosecuted in the exact same way they would if they created an infringing work via Photoshop or any other program. The same goes for other illegal uses such as creating harmful depictions of real people.

Accepting any expansion of IP rights, for whatever reason, would in fact be against the ethics of free software.