This is my opinion. The Traveler cannot defend itself without the assistance from sentient creatures. Therefore I believe its intentions were originally self-serving. But because it was overwhelmed, it now relies on the Guardians more than any other organism that has helped it in the past. It has had a change of heart, and it's self-serving intentions have changed. The Traveler knows it was being pursued, yet comes to our solar system to "protect" us. It brings with it death and destruction. We consume it's light just like the other factions. However, we idolize it, believing the light is a blessing. We consider it a god, rather than a means of survival. The Hive worship Oryx...who only wants the Traveler to serve him. The Vex seek the Traveler simply for fuel. I think the Fallen and the Cabal both stood in the shoes of the Guardians, but, much like a gambler gets addicted to gambling, became, for lack of a better phrase, blinded by its light. The Cabal and the Fallen seem to be on equal footing with us, without any gods guiding them. They are, however, scavengers, much like us Guardians (scavenging the wastelands for engrams and materials). Grimoire and history can be manipulated by the words used, as well as through the passage of time. In the case at bar, so much time has passed that many theories can be proven correct...or incorrect.