Anyone who has been around kittens knows that they don't like to sit still (unless they're napping, and then you can't get them to move). It's pretty obvious, however, that this dog has not been around too many kittens.
The well-meaning doggo mostly seems concerned that the kittens might get too far down the stairs, away from its watchful eye and their litter mates. So it scoops up the kittens by the scruff and carries them over to a comfortable-loking bed as if to say, "Here, isn't this nice? So warm and comfy. You'll just want to stay here forever."
Except the kittens are kittens, and they would much rather explore than be forced into some sort of plush cage with no bars. Or doors. Kittens just want to be free, dog! Or you could maybe invest in a pet gate. That might work, too.