Oftentimes the native intelligence displayed in our pets, causes us to think and react to them as if they are like us and have motives for their behavior similar to ours. (Which may be saying more about us than about them.)
We oftentimes think and react the same way with our little children.
Yes, they are natively intelligent. And, yes, they need to be taught correct behavior. What they need most, of course, is our love and gentle persuasion. And careful teaching.
The older we get (and thus the farther away we are from our own childhood), and the more hassled we feel, the easier it is to become impatient. And perhaps unnecessarily harsh.