Are Ts more prone to be vindictive because of a lower F function? Most of my T friends handle rejection or break ups poorly by pretending they are fine, trying to hurt the other person by preteding they are better off without them before detaching completely.
No. Anger is a universal human emotion and vindictiveness is a common extension of anger. Some forms of anger are morally justifiable. However, it is often the case that anger merely comes out of entitlement. If your core beliefs are rooted in entitlement, then you are primed to perceive negative events in terms of you being “robbed” of something. This makes you very easily triggered into anger and, subsequently, vindictive behavior that seeks to punish whatever you believe has wronged or robbed you.
Vindictiveness should be distinguished from justice; the former is the dirty work of a sad and wounded ego, whereas the latter is the noble work of trying to restore fairness to an unfair situation. When anger is morally justifiable, then it should be channeled into seeking justice, to rectify what was done wrong in a way that restores everyone's well-being. However, people with poor emotional intelligence tend to confuse vindictiveness for justice. Their actions are destructive to people's well-being, including their own. Poor emotional intelligence is not limited to Ts.
When a person is unable to regulate their anger due to being entitled, it is a sign of poor self-awareness, and perhaps even narcissism in extreme cases. Poor self-awareness goes hand-in-hand with poor emotional intelligence. Your type doesn’t cause you to have low self-awareness, but low self-awareness leads to you being a less than stellar example of your type.