Well, as far as villainous Urobuchi characters go, it's arguably the least evil one construed (...when applying human standards, potentially inapplicable as they might be). In that it actually seeks to further a purpose that would be almost universally recognized as a true "greater good" (the survival of the universe), through means that would almost universally be considered evil (tormenting innocent little girls). Hey, it's that whole utalitarianism vs. deontology thing Death Note never really did anything with. Only drawn up more sharply yet, and with a looming question of what the applicable perspective for making such an evaluation even is (there might even be more, ultimately reducing morality to a battle of interests...).
Thus, it comes down to perspective. From a human/earthly perspective the thing is obviously a harmful evil, in that it torments humans and is prepared to annihilate the planet to achieve it quota. However, from a sapient beings/universal perspective, it might be doing more good than bad by doing so... and it does not even have the logical (in)capability of understanding why/how humans might view its intent and actions as evil to begin with, making it hard to pass judgement on it.
It's a net negative from one perspective, a net gain from another, impossible to blame by conventional standards, and a very well executed conceptual character overall.