The Light and Darkness can't be described as good and evil. They are philosophies, and just embody different paths to peace. The Light and Traveler believe peace is reached through prosperity, and through this caring nature many come to call it "good". The Darkness believes peace can only be achieved by reaching the Final Shape, where only the little life that is worthy remains. That means violence is used for this philosophy, so people consider something so ruthless to be "evil". Good and evil is based on perspective. The Hive think that the Light is evil and they are good

Basically all the grimoire refutes it. The Traveler can be ruthless, that doesn't make it evil. Read the Book of Sorrow.

*cough*Books of Sorrow*cough*

I don't think its evil, just... like... careless. I have a theory... The Traveler is part of a race, something like the Forerunners, if you played Halo. The Forerunners existed to, presumably, guard and advance life. But The Traveler is kind of... a rogue. Instead of waiting for the races to hit a point, it rushes forward, uplifting races before their time carelessly for whatever reason we don't know yet. Its reckless in its choices, and skips from race to race hoping to find that "perfect specimen". Instead of evil, its more... like a scientist experimenting outside the established plans. Through the course of this, it accidentally created shitty races bent on hoarding power. The universe is an ant farm, and the Traveler is the observer, manipulating things.