The people of K'tau are a peaceful race, who live in protection thanks to the Asgard. The race is protected as part of the Protected planets treaty, and the people of the planet believe Freyr to be their god.
When SG1 came through the gate, they were thought to have been elves, however, when the planets light frequency changed, the K'tau people, believed SG1 to be the harbingers of Doom.
The K'tau people, being relatively naive, prayed to Freyr to help them, and when he did nothing, they sabataged SG1's plans to try and help them.
However, SG1 with help of the Asgard managed to save the planet and return the light frequency to its rightful state. Saving the people of K'tau.