I don't see rooting a phone as "hacking".
This is where it gets complicated (lol)
https://en.wikipedia.org/wiki/Hacker_%28term%29#Hacker_definition_controversyEssentially the term hacking covers much more than just subverting security.
Personally, I'd consider preventing an elevator from stopping on other floors to be "blackhat". You are now taking advantage of special knowledge about the elevator for your own personal benefit at the expense of others who are waiting for the elevator. Very selfish, and immoral.
Lets take a iPhone. You root it and install Cydia and decide to use free apps instead of the App Store. You have took advantage of Apple because they sold that iPhone at $600 and were depending on you to purchase apps to make most of the profit. You've now defeated their DRM and have caused them to lose out on this profit they budgeted for. You could say it is selfish and it is also illegal in many jurisdictions in some cases for this very reason:
https://en.wikipedia.org/wiki/IOS_jailbreaking#Legal_status