We can't comprehend the danger that could be caused by strong AI because we don't understand how to make worlds. Embedded within the fabric of the cosmos are the instructions for materializing a black hole from dark matter and energy. And though the recipe may be hidden from our mortal minds it's possible they may be discovered by a de novo thinking machine. A software system with infinite IQ but the moral sense of a one day old. An electronic brain that would have no compunction in creating a super massive black hole right here on Earth just to see if it can succeed. Irrespective of the consequences to humanity.
If this "Jupiter-sized" consciousness is allowed to have thoughts that are not "amenable to inspection". Even perhaps beyond comprehension. And the danger elides to the scale of a solar system with nothing but diamonds in it. Then, by the naysayers own logic, shouldn't all AI research be outlawed? Or at least confined to the equivalent of CDC-level-5 quarantine labs?
If on the other hand you believe that Nature has certain innate prophylactics. And that it takes more than a super will to bend the laws that govern space and time. You may be self-assured in thinking we as a species have at least a century or two before we really need to begin worrying about virtual immortals.