Cats Scratching House Furniture
The instinctive behavior of kittens makes that they scratch your house furniture. They enjoy it, and that upsets you.That's one fact, the other is that no matter how upset you get, you can't change that in a cat.
Cats scratch around to mark their territory, exercise and simply have fun.
All you can do is to create a small space for them, and guide them to scratch some old piece of furniture, so that they will leave your other furniture in peace.