To activate the root account in osx, you have to actually open some app and enable your user to access root. And your user has to be an "admin" user to begin with. Its not an easy process unless you know where to go (netinfo manager). Sure. do it from the boot disc. Not only is that annoying, its a pain in the ass. More so that enabling the root acount, and typing "su" in terminal.
Bascially, yes, OSX is built with open source tools. Its bascailly a free os. You can download darwin, and run osx without the gui for free. But what is OSX minus its friendly gui tools?