Because this is how it used to be done ~2.5 years ago, and it nearly led to the (what would have maybe only have been temporary, however, we will never know) ruin of the BTC economy, and would have, if some people didn't bail out thousands of BTC of default from their own pockets.
EDIT: This is the tldr version of the story.
So why wasn't legal action taken? Or maybe perhaps point me to the story? I'd like to read it.
Because more than one person was responsible for it, and it was too big of a mess, and involving legal action at that point would have damaged bitcoin's reputation, and plus people all over the world were involved, it simply was not feasible. Also, it's written in posts by people recounting the events, I don't know of any off-hand though, as I was there to witness it, so I didn't read it from an article somewhere.