Well, I don't agree with what seems to be the common definition of 'hacker' here. For me, hacking is the art (or vice) of making things do what they are not supposed (or allowed) to do. Plainly that.
Someone that builds a kick-ass revolutionary web application using Node.js is _not_ a hacker. He made a web site using a web site making tool. No rule bending anywhere.
Someone that builds a refrigerator for rural areas that works without electricity (as mentioned in another comment) is _not_ a hacker. He is an inventor. A genius. An engineer. Whatever, but _not_ a hacker.
Someone that takes a rotary telephone and manages to make it open keypad doors remotely (or whatever) is a hacker. A phone is not _designed_ to do that.
So answering your question, yes, for me, whoever bends the rules of machinery (even social or bureaucratic machinery) could be called a hacker.
But most definitely, 99% of people mentioned in this site should _not_ be called hackers.