The best thing that can be done is to hasten the turning of the Wheel. Killing the profane not only returns their being, their Atman, to the Wheel where they can be reincarnated into new lives, but it also halts their disasterous journey towards karmic retribution. As far as the Euthanatos are concerned, life and death are one and the same. Death, material death, simply means a return to the Sri Chakra, the Wheel. Death is only regrettable insofar as much of one's knowledge towards Ascension may become forgotten in one's new incarnation, but since Karman follows one from life to life, this is at best a temporary setback.
Wraiths are merely part of the process of Samsara, the cycle of rebirth.
Wraiths remain subject to the Karman which they accumulated in life, but in their present state are unable to continue pursuit of Ascension, which is why the Euthanatos value life so much. Many Euthanatos despise wraiths. On the one hand, wraiths are delaying the Wheel of Reincarnation. On the other, they only display their ignorance in thinking the living world any more 'real' or 'lasting' than their own. But although it is insubstantial, the world is not devoid of meaning, since it is through the world that Ascension is achieved.