Read the Book of Sorrows. There is nowhere to hide from the Hive. They will eventually consume the universe. This is their religion, in a way. Their philosophy. So with the Traveler we stand a fighting chance. Without him we are completely doomed. It is a story of the greater good. Yes he may put a race in danger by exposing them to servants of the darkness, but the darkness must be stopped somehow before it destroys all sentient life. And the only way to do that is to use the Travelers light to fight it.