Disrespect is a paper tiger. It comes at you looking like something, and it has never once actually done you any damage.

What the research says

A review of the neuroscience of anger describes reactive aggression as arising from a basic threat system involving the amygdala and related structures, which frames sudden anger as a defensive response rather than a chosen strategy. That fits the feeling of being under attack when nothing has touched you. It is a review setting out a model rather than a test of it, and it explains the reaction without excusing what comes after.

Strength of evidence: one line of research. A single study, or a theoretical account.