If self-sacrifice isn't worth it then willfully planning the sacrificing of someone else isn't worth it. After all... Think of the good that person might yet still be able to accomplish.
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Are the Wraith really evil? They have no choice as to what they eat, and while they go about things in an evil way, does that justify genocide?
Obviously we cheer the humans, being human. But if we were wraith... Well, kind of story do you think this would be for them?
Seriously? Moral relativism is your argument?
Okay so this derails quite a bit from the thrust of the main story... but, Evil is a choice, and there was at least one episode where the wraith where offered the choice to use an experimental treatment to reactivate their stomachs and deactivate their palm feeders.
Now I'll, grant that the treatment as understood by the Atlantis team was a failure since the wraith involved would experience health concerns while their biology fought against the treatment. But I'll also point out that the wraith michael had a version that was successful to a point, though he still managed to be evil even with it.
And as far as we knew, the wraith quite possibly could've chosen to drain the life from mere animals instead of humans, though I believe if it was brought up at all in the show, the wraith dismissed animals as lacking the "taste" that humans have.
You may argue the point, yes, that they have a different understanding of morality where their food supply is concerned. Just there's a difference between sophants and... Livestock.
Justification isn't everything and doesnt automatically exonerate or absolve the liability for actions taken. Nor should it convey any legitimacy beyond a recognition of the factors involved in shaping a concern.
Yeah sure, the wraith are aliens, and thus alien to human expectations, thoughts and behaviors. However just because some group is alien does not instantly absolve them of responsibility for their actions and behaviors.
My point, the wraith did have options, they could've chosen to devote some of their biomancers to the task of reducing their need to feed on sophants, they didn't, instead they decided to use hibernation and periodic cullings when the population recovered enough. Hell they've been known to drain their own kind in the absence of other options.