This is an example of a stressor (divorce) inducing the immature defense mechanism "Acting Out" which FA defines as: Expressing unacceptable feelings and thoughts through actions.

And the answer is, acting out aka “being a teenager.”

reaction formation "in psychoanalytic theory, a defense mechanism in which unacceptable or threatening unconscious impulses are denied and are replaced in consciousness with their opposite. For example, to conceal an unconscious prejudice, an individual may preach tolerance [...]"

https://dictionary.apa.org/reaction-formation