It doesn't seem to me that, unless we're putting humanity's self-interest in conflict with some other hypothetical alien civilization, that the rest of existence has an opinion on humanity's continued existence. The universe, insofar as we know, is pretty indifferent to the state it's in, and the only frame of reference we have in terms of values to decide whether or not humanity should continue is... well, humanity's own myriad value systems, which, unless fully misanthropic, generally have a group of humans, or humanity overall's continued prosperity as a good as a fundamental of the value system.