Can We Just Turn Off Dangerous AI?

There's this meme out there to make people who care about artificial intelligence safety look crazy. If AI ever starts doing something that might destroy humanity, we'll just shut it off. AI requires power and computers to function. So, if machines start building nuclear weapons of their own free will or turning everything into paper clips, we'll have no problem. Some prominent voices on the topic try to refute this argument by saying we don't know the types of extremely strong arguments and persuasion a hyper-evolved machine can produce.