tone policing

Tone policing is dismissing or deflecting an argument by criticizing how it's expressed rather than engaging with its substance.

The term emerged from social justice discourse, where marginalized people's anger or frustration is often used to invalidate their points: She was told to calm down before anyone would listen—classic tone policing.

The implicit demand is that grievances be aired politely, which critics see as a way of protecting the comfortable from uncomfortable truths.