I swear it wasn't me

So, I'm reading this book from the library (The Skeleton Crew, review coming soon), minding my own business, not even looking for errors or anything. I admit that occasionally my proofreader brain won't shut off, and I spot typos, lack of the Oxford comma, or the wrong [itz], and rage a little bit. But I would never, I repeat never, write in a library book. 

No matter how much I might (fiercely, desperately) want to. 

It looks like this person, though, just couldn't contain themselves. 

It's not a very happy book, sorry. 

Why is this so? That the past tense of hang in the sense of "kill by hanging" is "hanged," not "hung"? I really have no idea. Nor does anybody else who is Googling things, as it was the third-most popular suggestion for "Why is the past tense of..." 

The OED etymology for this particular little word is massive, and goes on about Old Germanic strong and weak verbs, throws in a bit about Old Frisian, and brings in the Bible and Shakespeare. It's all a bit dense and boring. But the most relevant bit, I think, is this: "...leaving hanged only in the special transitive sense (3) ‘put to death by hanging’, owing probably to the retention of this archaic form by judges in pronouncing capital sentences." Which is to say, legal jargon is conservative, and hanged was once upon a time in more regular usage. 

Now, isn't that a nice way to start off the week? </snark>

xo, 
Devo