Displacement of aggression from a threatening target to a less threatening one is a common human and animal practice.
If we are angry at our partner we may kick the cat or nag at the children instead of confronting the real target. Freud stated that in dreams we express what we usually censor, or would be censored socially, in terms of behaviour or sexuality, but often in a displaced way. What appears to be most important and full of emotion in the dream may, according to this statement, be really of least significance.
[1]