Fisto (78):
"Now tell me Mark, does this not logically track to the absurdity of killing off some of the population we already have? Does this not lead to the question of who deserves to have/survive? I'm not saying that Nic himself believes this, I am saying that these premises lead to these absurd and cruel consequences."
I don't believe that that's the only conclusion that can be reached.
Nic is suggesting that the people of planet earth would be better off if there were fewer of us rather than more, but that doesn't necessarily lead to the conclusion that we should start killing people off - because he's not asserting that there is any immediate solution to the problem. He is suggesting that there are options for reducing the overpopulation problem in the future (and these options do not involve killing people off).
Another conclusion that can be reached is that there is no immediate solution to the overpopulation problem (short of killing people off which is obviously immoral) so we just have to accept that we have the number or people that we have and deal with the problems as best we can, but there are options for reducing the problem in the future (though those options are morally questionable as well).