Uhm, do you know anyone who has or is serving in the military? Sorry, but you are wrong. They don't all turn into cold killers, nasty and mean. Most don't. Yes, being a soldier does change you and those in combat can go through some life changing stuff. Yes, they learn to compartmentalize. Anyone who has to see or cause or be around lots of ugly death has to or they won't survive long enough to do the job. This doesn't make them cold or unfeeling. This makes them responsible adults in a hard situation. This happens to soldiers, doctors, emergency personnel. They have to stay in control. Kennedy was anything but and she was always trying to stir everyone up.I can't believe I'm defending Kennedy here, as I can't stand her, but I think her behaviour in season seven makes more sense if you take into account the themes of that season. What is a slayer? The final season addresses the meaning of Buffy's calling more than any other, albeit sloppily.
The slayer is like a soldier -- an emotionless tool of another institution (the army is the government's tool, the slayer is beholden to the watchers and a 'primoridal' power). They're fighting a war, but the reality is that war is institutionalised rage, and no matter how respectable Americans think their veterans to be, all soldiers are trained to be killing machines. No room for emotions and Dr. Phil.
Kennedy is a accurate example of what happens to a soldier. They become cold killers...nasty and mean. So did Buffy in season seven. They could have made a brilliant sending off to the show had they harnessed this theme more maturely.
Although I would love to have seen the psychological aspects of fighting a secret and potentially unsurvivable war explored, I don't think that Kennedy is a good example of battle fatigue or PTSD. She just seemed spoiled and willful.
I do believe Buffy did harden herself in order to survive the war she saw was coming, but I think she had a unique situation -- try to survive and to save the world without much help, and with the added burden of becoming responsible for 30 odd useless, frightened kids who showed up requiring food, training, protection and constant reassurance.
Every good senior officer knows he/she will have to send people out to die and so they must learn to face that. The situation in Sunnydale was that she had all of the burdens and none of the authority, as she was being constantly undercut by Giles, Willow, Xander and even Dawn. The only people who don't try to take her power are Spike and oddly, Faith -- though Faith ends up with Buffy's responsibilities and what leadership power Buffy had had being dropped in her lap. That didn't go well, but since she had none of Buffy's experience and no training from Giles or anyone else, that wasn't her fault.
Kennedy was out of control. She's not an accurate portrayal of trauma of any kind, though she's obviously scared and that's a reasonable thing.
Kennedy had no loyalty or respect for anyone. She thought she had the right to order people around and be rude and hostile and she shoved her way into Willow's bed That is NOT how you open someone up after a loss. She just acted like any random soldier who wants to get laid in a war zone -- she pushed until she got what she wanted. Frankly, I don't hate her mostly because I cannot bring myself to care about her and I don't really want to bother with thinking about her.
Season 7 was poorly written and the potential story line was horribly realized. Kennedy was not that high on my list of what was wrong with season 7. She was just part of the ugly whole. I don't think she's evil, but she's uncaring and self seeking. I know peopel like her. She's a narcissist. I don't wish those on anyone. They lack any empathy. That worse than being cold.