I mentioned duplication. That in 3^^^3 people, most have to be exact duplicates of one another birth to death.
In your extinction example, once you have substantially more than the breeding population, extra people duplicate some aspects of your population (ability to breed) which causes you to find it less bad.
The other observation that occurred to me is unrelated. It is about the idea of harm being nonlinear, which as I noted above is just plain not enough to invalidate the torture/​specks argument by itself due to the ability to keep thwacking a nonlinear relationship with bigger numbers until it collapses.
Not every non-linear relationship can be thwacked with bigger and bigger numbers...
I mentioned duplication. That in 3^^^3 people, most have to be exact duplicates of one another birth to death.
In your extinction example, once you have substantially more than the breeding population, extra people duplicate some aspects of your population (ability to breed) which causes you to find it less bad.
Not every non-linear relationship can be thwacked with bigger and bigger numbers...