The order have come to understand that having emotions is something that makes no sense for the sake of their progress. They do experience emotions, but they don’t experience human emotions. What they experience is a completely different set of feelings that are incomprehensible for humans. If humans had the chance to grasp these type of feelings, the world would be a completely different place.
There would be no drugs, there would be no wars, no sexual crimes, no envy and no need to compete against others. The way that the order works is completely different. There are many reasons why the members of the order have saved humans from extinction, but none of them involve love or any other emotions at all. They are all related to the experimental use of other species to create new colonies and see how they behave and evolve.