There is some objective morality, though. People agree that it is right to avoid violence, look after another, and speak kindly for the most part after all. The guardians are not *usually* the aggressors in situations. Savathûn, while still being reborn as a guardian, was still manipulating people and trying to steal the Traveller. Not even mentioning the fact that all of her memories are basically restored, making her bearly the same Savathûn that would find it necessary to take control of Osiris as a flesh puppet and try to massacre the fallen and kill the people of The Last City. I guarantee revived Savathûn would have seen the same action as "necessary." Watch Megamind. Bad guys don't have to stay bad. Morality is chosen. (an exception is pathic mental disorders on some occasions)