Many things can be unethical/immoral without being illegal, and of course there are some technologies that are fundamentally bad.
Let's say that the tech around this DeepFaceLive repo develops to the point that the repo can become just a 10-line file of glue that makes a 3d model that's just a grid plane with a picture on it that moves according to a webcam feed. Such a repo is redundant and anyone that wants this tech can just apply the repos mentioned in the previous paragraph to do the equivalent.
Are those repos now bad? If not, it seems the ethical question can be resolved by some restructuring of code so bad uses are not made so obvious, while being almost as easy.
Nuclear weapons and the advent of mutually assured destruction has ushered in a world where many, many, many fewer people die of violent conflict.
Technologies that cause destruction are not congruent with destruction. They change the game such that destruction may actually be prevented by their existence. They are tools, nothing more.
It's possible they have permanently eradicated world war. If that's true, they are not fundamentally bad but in fact really quite great. Only time will tell.