Well, yes? If Roko's basilisk was true, it'd be unethical to spread. It turned out to not be true, but if Roko was reasoning from the premise of it being true,

Well, yes? If Roko's basilisk was true, it'd be unethical to spread. It turned out to not be true, but if Roko was reasoning from the premise of it being true, or even possibly-true, then the action was still unethical.