How exactly does apple do it?

Okay guys I recently (LOL) stumbled upon what's known as hacking tosh and to my surprise no BIOS setting are really modified to allow one to install OSX_x-x-x (LOL) on a normal PC. DOes anyone atleast have an idea cos all I see are changes being made to the type of devices to boot from and the type of harddrives used. Thanks. PS: I do not intend on running any apple stuff I just want to know why the seem to brag about security if hacking their OS is so simple. I LUV LINUX UBUNTU!!!!