Assuming the celestials were telling the truth, life is dependent on their existence. Just as humans must consume other life to survive, the celestials must consume life, and in doing so, allows new life to come into being.yeah its pretty much agreed that Celestials are villains, however notions of good and evil are rather meaningless to them - they think of humans as lifestock not people.
but yeah now knowing that the energy from the Tonga eruption was felt from NZ to Japan and Alaska, it does seem that the emergence of Tiamut should have been far more devestating
it is the circle of life, not good or evil…but ultimately necessary.