The "decapitation as castration" idea has come up, and damned if it doesn't bug the living shit out of me.
The idea basically seems to go that your identity, personality, and power is all contained in your head. Therefore, losing your head makes for a particularly degrading death because your body's been separated from all of that. It's equated to castration because that's an obvious loss of potency.
To look at a decapitation scene and call it symbolic castration is awfully backwards to me.
You see, the underlying attitude is that castration is a loss of identity, life, or power. Its root lies in the hypermasculine society that devalues all femininity. It hinges on the belief that the very worst thing possible is not to have a penis. It's an idea from a society that places all value and power into the male sexual organ. The same sort of logic that considered sperm the "Seed" -- the carrier of all that was needed to make a person, while the womb was simply soil to grow a person in. In this mindset, he penis holds your personal power and identity, so losing it is like losing that heavy thing on your shoulders that happens to hold your mouth, eyes, face and brain. Castration is a symbolic decapitation.
Castration's equivalent for a woman is actually becoming barren -- which is what happened to Black Canary in The Longbow Hunters. Another symbolic decapitation.
Decapitation itself is not a sexualized or gendered death.
While the preferrred execution method of criminals in some cultures, decapitation is a warrior's death when it happens on the battlefield. The shame associated with such a death is the shame associated with losing a battle. And yes, a sexism and castration parallel can easily enter into it. In such an instance, the victor holds the severed head of his enemy in his hands and declares that his opponent was weak and soft, like a woman, because (according to a hypermasculine culture that equates strength with masculine prowess) loss in battle can be attributed to either being a manly warrior up against someone who far outpowers them, or a pathetic, effeminate creature not suited to the manly arts.
When a female character's death occurs by decapitation, in the heat of battle, the nature of the death is non-gendered because decapitation is a non-gendered warrior's death.
It's one thing, of course, to find sexism by focusing on the reasoning why, or the reaction of the other characters to this death. However, to focus on the method of death itself, and how humiliating and degrading it is and connect that with castration when it is a death that occurs no where close to the sexual organs, and occurs on a battlefield rather than a traditional women's setting, comes dangerously close to the attitude that one's identity, personality and power lies in one's sexual organs. It also, when all the shame connected with a death in this matter comes specifically from losing the battle and not one's gender role, comes infuriatingly close to equating "loser" with "woman."
That particular line isn't crossed by simply engaging in the intellectual exercise, and going through a Freudian reading of the text. The line's crossed when it seems like its coming not from analyzing someone else with Freud's theory, but when the analysis is shown by someone wit the attitude that "women" = "weak." It's the difference between an objective eye seeing that something "could be taken this way", and a fanatical devotion to "must be taken this way" to the point that all evidence to the contrary is rationalized away.
That would be is where the blinding rage wells up.
When the attitude of an analyst overcomes an analysis of an attitude, it becomes a bit difficult to debate the fine points of Freudian theory.
(Oh, and thanks, Revena, for the input on this post)