It is said that this place is crowded with countless demons. They, whose purpose is to destroy, won’t benefit from protecting living things aimlessly. Therefore, they forbid keeping pets in Katarto mountains.
I may be making mistakes but I hope this makes sense.
"It seems that there are a lot of demons in the Katâto Mountains. It is said that they are not allowed to have pets because their purpose/mission should be to kill living creatures, not to take care of them, which would be against demons' purpose and wouldn't be proper. "
I feel a jokey/funny tone in it.
There is a contradiction between killing animals and taking care of/feeding/keeping alive animals, indeed.
There are many demons there. Some of them are "decent and kind" demons who want to have pets. But it would be "illegal" in their society.