A lot of angry certainty is frightened certainty. Needing to know exactly what is going on, and exactly who is at fault, is more comfortable than admitting the situation cannot be fully read.

What the research says

In two longitudinal samples of crime victims, post-traumatic stress symptoms predicted later anger more strongly than anger predicted later symptoms, which suggests anger can sit downstream of threat that has not been worked through. Anger following fear rather than causing it is at least consistent with what is described here. In a separate cross-sectional sample of inpatient substance users, particular kinds of childhood abuse were linked to aggression and to difficulty handling emotion, though cross-sectional data cannot establish the order.

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