From a completely practical standpoint... if we deserve to live, we'll live.
We're still alive, hence we have earned the right to live. Very straightforward =p.
If we're a failure as a species, then we'll die out one way or another at some point, either by destroying the means by which we sustain ourselves, outright destroying ourselves, or creating/inciting something that destroys ourselves.
From a moralistic standpoint, well... that depends a lot on the values system of the individual doing the judging ~~
For example, is life even a good thing? Some ideologies consider life suffering or punishment. Then the question would be, what ill have we done to be made to live?
I think that unless we do something especially heinous, like wipe out another sentient species in aggression, or destroy most of the biosphere of Earth or another planet, we're pretty much okay to keep on going. =p
