Yes that is their model of AI risk. However the people worried about AI risk are not worried about any single organization controlling AI. They are worried about a world where no one controls AI.
Controlling AI is actually a very difficult and unsolved problem. OpenAI is not intended to solve that problem, and if anything they are making it far worse by accelerating AI research before the problem has been solved.
AI is the only thing I believe has a very high probability of destroying all humanity. Probably within our lifetimes. And there is probably something we can do about it right now - working on the control problem.
All of them are real dangers, and present dangers at that. But they still are not existential dangers. Even in the worst case humanity wouldn't go extinct. It's unlikely even modern civilization would collapse, just a few countries.
AI is one of the few things that can literally wipe out humanity, or even the entire universe. So I think it's worth special consideration. Personally I also believe it's far more likely as well. And people are already doing things about climate change and nuclear proliferation. Until very recently, there were only a few people working on AI risk, and it's still nowhere near enough.
AI is a threat that is immediate in time. There is plenty of reason to believe we will build it, and probably within our lifetimes. And unlike aliens, there might be something we can do about it. Whereas aliens would be so far beyond us technologically it's very unlikely we can do anything to stop them.
I know you are just pattern matching "both of those things are from science fiction, therefore shouldn't be taken seriously". But there are actual reasons why aliens aren't taken seriously and AI is.
* except [human intelligence] / [human civilization]
Resources help it fulfil whatever it's goal is, and the more the better. That includes energy and computing power. Which it could gain a lot of by converting the mass of the solar system into a dyson swarm. Or covering the Earth with solar panels or fusion reactors and comuters. Etc.
Self preservation would be optimized by destroying anything that has even a tiny chance of being a threat to it. Even if humans are harmless, we could build other AIs like it which might compete with it. It's best to just destroy us.
The problem is the AI doesn't need to want to eliminate us. It will likely be entirely indifferent to us. We just need to be in it's way.
Among other reasons, we're made of matter that isn't actively contributing to its value function as efficiently as it could be.
Any AI that doesn't actively value sapient beings will very likely destroy them as an unintentional side effect of whatever it intends to do.
"Before superhuman AI is developed, the techniques that make it possible will look dangerous."
That's a risky proposition. There's so much to lose in this situation. Elon Musk, Stephen Hawking, and many other people are taking a different, more risk-averse bet:
"Superhuman AI is extremely dangerous, so we need to be pessimistic about how good we are at predicting when it will happen."
By that logic, general AI is to be feared and worried about right now, because our predictive abilities are imperfect. The AI trend is towards more danger, not less: there's a slight chance of a cataclysmic event happening today, and as time goes on, the likelihood of it happening will increase (due to ongoing R&D in AI).
(As an aside, if you want to learn how hard the "AI Control Problem" is, I recommend the book "Superintelligence" by Nick Bostrum.)