Yes, I feel much safer

I'd be depressed if I got arrested for an overdue library book

"why is this happening?"

That's because it's easier to arrest someone who has broken a small rule like this than someone who murdered two people in a disturbing fashion. It's not that they don't get arrested, (well, yess it is) but it's that this happens often and sometimes police can get caught up in a guy who forgot to return a book instead of a guy who murdered three people with a chainsaw. By the way, your comment doesn't save lives either, now does it?