2. The "too dangerous to release" refers to the text generation mode of GPT-2 and was mainly targeted at spammers etc.
3. Of course there was a hype component in it. They wanted people to start thinking about the question before it's too late, which they did. I doubt that we'll get any kind of attempted world control takeover by AI (unless someone explicitly tells AI to do it, at which point it's a guy trying to seize world control with the help of an AI tool), but even if the chance is very small, if you multiply it with the damage, you should at least start wondering about countermeasures.
To get philosophical I won’t say that I “know” it’s happening. Most of the world consists of things I don’t know about. The best I can do is build a mental model based on what I do know.
Why aren't bad actors using it in the wild? I think it's a combination of them being technically unsophisticated and conservative, propaganda not actually working nearly as well as people like to think it does, and lack of detection of competent actors (things like StyleGAN being used for fake FB profiles are detected through carelessness like leaving the faces exactly aligned).
One trained model is not enough to judge transformers. Listed to this: