I think it is almost always assumed that superintelligent artificial intelligence (SAI) disempowering humans would be bad, but are we confident about that? Is this an under-discussed crucial consideration?
Most people (including me) would prefer the extinction of a random species to that of humans. I suppose this is mostly due to a desire for self-preservation, but can also be justified on altruistic grounds if humans have a greater ability to shape the future for the better. However, a priori, would it be reasonable to assume that more intelligent agents would do better than humans, at least under moral realism? If not, can one be confident that humans would do better than other species?
From the point of view of the universe, I believe one should strive to align SAI with impartial value, not human value. It is unclear to me how much these differ, but one should beware of surprising and suspicious convergence.
In any case, I do not think this shift in focus means humanity should accelerate AI progress (as proposed by effective accelerationism?). Intuitively, aligning SAI with impartial value is a harder problem, and therefore needs even more time to be solved.
I just don't think it makes any sense to have an aggregated total measure of "welfare". We can describe what is the distribution of welfare across the sentient beings of the universe, but to simply bunch it all up has essentially no meaning. In what way is a world with a billion very happy people any worse than a world with a trillion merely okay ones? I know which one I'd rather be born into! How can a world be worse for everyone individually yet somehow better, if the only meaning of welfare is that it is experienced by sentient beings to begin with?
It's moral because the terrorist is infringing the wishes of those people right now, and violating their self-determination. If the people decided to infect themselves, then it would be ok.
I disagree that the genocide is made permissible by making the death a sufficiently painless euthanasia. Sure, the suffering is an additional evil, but the killing is an evil unto itself. Honestly, consider where these arguments could lead in realistic situations and consider whether you would be okay with that, or if you feel like relying on a circumstantial "well but actually in reality this would always come out negative net utility due to the suffering" is protection enough. If you get conclusions like these from your ethical framework it's probably a good sign that it might have some flaws.
Rocks aren't sentient, they don't count. And your logic still doesn't work. What if you can instantly vaporize everyone with a thermonuclear bomb, as they are all concentrated within the radius of the fireball? Death would then be instantaneous. Would that make it acceptable? Very much doubt it.