I'm not saying there's an 0.0001% chance of it happening, I'm saying that if you give enough people a chance to create an AI, eventually someone
will do it, even if 99.999% of people would choose not to. Right now, nobody knows how to do this, but my point is that eventually people will figure out how: once everyone knows how, then it's just a matter of time before someone does it.
I'm not second guessing human nature, just saying people do crazy things all the time. The vast, vast majority of people are not suicide bombers, for example, but it still happens sometimes. It doesn't matter how much collective responsibility we have; eventually you may just end up with a brilliant programmer with schizophrenia or something who writes an AI in his basement and unleashes it on the world.
I'm also certainly not resigning myself to catastrophe. There are probably ways to prevent or mitigate the negative impact of AI, like the one being suggested in the original article, for instance. I would hardly consider myself a cynic, but forgive me if I'm skeptical of the idea that every human in the world can somehow agree to never do anything that might create a dangerous AI. If it can happen, it eventually will happen.