Is Prego disciplining Polly?

Prego (my adult cat) grabs Polly (5 month old kitten) by the scruff of the neck, then pushes her head to the ground, then meows repeatedly. Is this some kind of kitty discipline? I've noticed the circumstances under which he does it the most. She meows at the door trying to go outside (I don't let her out.) Prego does not like that. He grabs her neck at other times too, but this is when I have noticed it especially. I thought maybe he was trying to teach the little one proper behavior. He is not hurting her, and she's certainly not afraid of him or trying to avoid him (she pounces on him as much as ever), so I have not stopped him from doing it. Am I doing the right thing? Does anybody else's kitties do this?

Pepper will do that to Scooter when he is annoying her. She thinks he is her baby, even though he is a year old, and she adopted him when I brought him home. As long as she is not being hurt, it should be ok to let them sort it out.