[smaudet]

Again, infinity is illustrative.

Put another way, you do not deny a proof by inference because it "leads to large numbers".

We don't need to speculate, we can see many, many examples today of more and less intelligent species, and also what happens to the less intelligent ones, even taking humans out of the equation.

I'd argue, even a machine intelligence that merely managed to be mildly smarter than us would be a threat. AGI merely has the potential to be infinitely smarter than us, but that's somewhat irrelevant given we might not even be smart enough to realize how much smarter they are (a cat will likely not appreciate the difference in intelligence between a dog, an elephant, or a dolphin, despite all those animals being generally smarter).