why narcissistic silent treatment
Once he gives up on his erstwhile Sources of Supply, the narcissist proceeds to promptly and peremptorily devalue and discard them. This is often done by simply ignoring them  a facade of indifference that is known as the silent treatment and is, at heart, hostile and aggressive. Indifference is, therefore, a form of devaluation. People find the narcissist cold, inhuman, heartless, clueless, robotic or machine-like.