Why did Katniss kill President Coin?

Could you elaborate on the motivations behind Katniss's decision to take President Coin's life? What events or conflicts may have led her to such a drastic action? Was it a personal vendetta, a matter of principle, or perhaps a strategic move to achieve a greater good? How did her actions align with her beliefs and values as a character? Did the circumstances surrounding the killing reflect a broader theme or message in the story?