Stalin controlled the state. The state controls companies. Companies control watermarking.
This sort of solution to the fake image problem, makes it easier for stalin not harder. If everyone can make fake images that is one thing. If only the dictator can, well that is much worse.
Why are humans powerless to do anything about this? Aren't we making the technology? It's kind of a big problem for the future of the justice system and politics.
Do you want to make it easier for the next Stalin?