“Circumstances don’t make the man, they only reveal him to himself.” —Epictetus
In Bolton’s case they reveal a vengeful self-absorbed careerist as you described. When big people have the chance they rise above a bad situation and have mercy on others unless bringing them to justice has a role. Bolton was fired and is so small and petty he lies and slanders another man without hesitation or restraint.
Where David in the Bible would say how can I sincerely repent, Bolton says “Which cameras will be on me when the segment starts? I have some new things to say against Trump.”