This is the difference between J&K. Jon actually interacts with his kids when he is with them. Kate on the other hand, yes she is "around" them but she never really interacts with her kids.
She just stands there and post for the cameras. Pretending to "play" with her kids. If not that, she is yelling or screaming at the top of her lungs.
See here, here, and here. Notice how she looks at the cameras.