Ultimately you end up back at the beginning: holding people, and not pieces of information, accountable for their actions. That's an issue with civil society, not social media.
Plus, deepfakes have the potential to create much more noxious videos than real life. Real life videos depict real life people, flaws and complexities all included; deepfakes will be constructed to depict representations of the target that're most likely to generate inchoate rage of the mob. It's rare that the former happens to be exactly the latter.
Why not blame the person who confirmed your husband's death at this point if accepting comfortable illusions of someone easy to punish is what we are doing? Without them you would still have some remote hope of survival!
The first step of solving a problem is recognizing the actual problem - what we find comforting is only a distraction for rationalization purposes. Better to recognize that microscopic organisms caused the crop failure instead of burning an old woman as a witch.
Politicians don't have a particular right to remain in office despite inciting violence, even if it gives them the sads if they face repercussions.
If the video weren't fake, would that somehow make the murder of Rohingya acceptable?
Your answer is astray. What is at stake is evident : one can now provoke riots and deaths from thin air (and bits).Just one example: A radio station (RTLM) in Rwanda laid the groundwork of genocide by dehumanizing Tutsis, among other things by referring to them as "cockroaches" repeatedly. The station was deemed instrumental in the resulting murders of at least half a million people.
It's not fear mongering to look at the facts of history and see that propaganda is a primary way that violence scales. Deep fakes are another tool which will certainly be used towards these same ends. What propagandist would not want to use such a tool?
Propaganda is a primary way that human action and organization, whether violent or not, for good or ill, scales.