They had heard humans liked to camp outside from time to time to relax and enjoy themselves. There was no scientific research for it, they had good homes to live in, but humans, as they said to some of their companions, just liked to "rough it" from time to time. So, the havenworlders invited a group of humans to show them how to "rough it" on their world. By human standards, this world was an incredible paradise. To the havenworlders, the night time was a frightening thing due to all the large animals that came out. -- DaniAndShali
Of course the Humans had built a fire. It was a contained fire, but it was still a large fire for the Havenworlders. Though the taming and use of flame was one of the more important steps into cogniscent civilisation, Havenworlders considered it a mark of advancement to get as far away from using fire as possible.
Meanwhile, Humanity took three centuries to finally abandon making steam to create power, and still had an almost unnatural fascination with flame.
The Humans on this expedition hadn't even bothered to put up tents. They were lounging around on the soft mossy hillocks and looking up at the stars, completely at ease. They seemed to have no idea that the night was dark and full of terrors. Therefore, Uisse attempted to tell them. "You must make shelters and hide. The big beasts will come out."