I am disappointed in the level of fear-mongering pearl clutching; it could[0] get so much worse! First, the person creating the fakes is using an off-the-shelf algorithm[1], adapted accordingly. A system designed purely for the purpose of swapping faces (or morphing a particular face into others, one-to-many style) would obviously yield improvements. Secondly, it's the work of one person without commercial backing[2]…
if fake porn does become ubiquitous as you argue, wouldn't the impact of such assassination be greatly diminished?