A Simpler Scenario

[nrenka]

>> Pippin:
>> Why then have such a horror of this one particular spell? 
 
> Kneasy: 
> Because it has only one purpose and it's supposed to be unstoppable.

And that fits in with Rowling's metaphysics, too.  She says that what 
makes Voldemort so evil is that he kills, and dead is dead is dead in 
her world.  She's also made comments about how awful it is to take a 
human life.

Given the model we've been shown of intention powering the 
Unforgivable Curses (Crucio clearly, the others more implies), AK is 
an evil, evil thing precisely for Kneasy's reasons.  It kills people, 
it can be stopped by inanimate objects (but blasts them apart), but 
the only person who has ever 'survived' it is Harry, and for specific 
reasons.

IMO, it would also really defang the end of the book to then go "But 
it was a fake AK, and Snape cast this other spell instead, and..."  
The interest is in *why* Snape did such a horrific thing.

-Nora watches the sun set, entirely too early