But that's the thing. Thinking about killing someone, planning to do it, is very different from actually reaching the moment when you have to do it. Surely you've seen hundreds of works of fiction where a protagonist has planned for a long time to kill someone, prepared for it, trained for it, hunted them down, and then realized at the last moment that they couldn't do it. It's hardly an uncommon character arc. And there's real-life precedent for it too. In wars where the majority of soldiers are drafted rather than career military, it's been found that the majority of them deliberately shoot to miss the enemy. They're drafted to kill, trained to kill, judged ready to be sent into the fight, but they still have a change of heart and can't go through with it. And Kendra was pretty much drafted into this fight.
In any case, I stand by my point. Compassion and love may not necessarily be the best option in some situations, but I will never agree that they should be dismissed as stupid. Violence is stupid. Hate is stupid. Any mindless force of nature can kill. The ability to kill doesn't make you smart or superior -- it just makes you on a par with a falling rock or a virus. Love and compassion are constructive forces, forces that counter entropy and promote growth. They're humanity's dominant survival traits, the abilities that enabled us to work together, pool our resources, and create civilization. There may be circumstances where they need to be set aside temporarily, but in the long run they are far stronger, smarter, and more important than hate or violence or "toughness."